All known delayed palindromic numbers

Last updated:
June 23, 2022, 0:05 UTC
Current world record (the most delayed palindrome): 25‑digit number 1,000,206,827,388,999,999,095,750 that solves in 293 iterations.

In the tables below only the smallest one of all known delayed palindromes is specified for each number of iterations from 1 to the current world record. Most of these numbers are reliably smallest delayed palindromes (RSN). But some of them are still considered as candidates and are marked with the CND tag, because there are untested numbers in front of them.

Number Steps Digits Resultant palindrome
All 1-digit numbers Lychrel numbers: none
1 1 1 2
5 2 2 11
Number Steps Digits Resultant palindrome
All 2-digit numbers Lychrel numbers: none
59 3 4 1111
69 4 4 4884
79 6 5 44044
89 24 13 8813200023188
Number Steps Digits Resultant palindrome
All 3-digit numbers Lychrel numbers: 13 (1.444%); search depth: 90M+
166 5 5 45254
188 7 6 233332
193 8 6 233332
829 10 8 88555588
167 11 8 88555588
849 14 10 8836886388
177 15 10 8836886388
999 16 10 8939779398
739 17 10 5233333325
989 19 11 89540004598
869 22 13 8813200023188
187 23 13 8813200023188
Number Steps Digits Resultant palindrome
All 4-digit numbers Lychrel numbers: 236 (2.622%); search depth: 30M+
1,397 9 8 88555588
2,069 12 8 52788725
1,797 13 10 8836886388
1,798 18 11 89540004598
6,999 20 14 16668488486661
1,297 21 13 8813200023188
Number Steps Digits Resultant palindrome
(only the first 20 digits)
All 5-digit numbers Lychrel numbers: 5,842 (6.491%); search depth: 1M+
10,797 25 16 1676404554046761
10,853 26 16 4455597447955544
10,921 27 16 4455597447955544
10,971 28 16 8802202552022088
13,297 29 18 893974888888479398
10,548 30 17 17858768886785871
13,293 31 17 17858768886785871
17,793 32 17 44035358885353044
20,889 33 17 44035358885353044
80,359 37 22 Loading...
13,697 38 22 Loading...
10,794 39 22 Loading...
15,891 40 22 Loading...
70,759 47 26 Loading...
70,269 52 28 Loading...
10,677 53 28 Loading...
10,833 54 28 Loading...
10,911 55 28 Loading...
Number Steps Digits Resultant palindrome
(only the first 20 digits)
All 6-digit numbers Lychrel numbers: 109,874 (12.208%); search depth: 1M+
700,269 34 22 Loading...
106,977 35 22 Loading...
108,933 36 22 Loading...
600,259 45 26 Loading...
131,996 46 26 Loading...
600,279 50 28 Loading...
141,996 51 28 Loading...
600,579 57 31 Loading...
147,996 58 31 Loading...
178,992 59 31 Loading...
190,890 60 31 Loading...
600,589 63 33 Loading...
150,296 64 33 Loading...
Number Steps Digits Resultant palindrome
(only the first 20 digits)
All 7-digit numbers Lychrel numbers: 1,897,107 (21.079%); search depth: 23,000
1,009,227 41 23 Loading...
1,007,619 42 22 Loading...
1,009,246 43 23 Loading...
1,008,628 44 23 Loading...
1,007,377 48 28 Loading...
1,001,699 49 27 Loading...
1,009,150 56 28 Loading...
1,058,921 61 32 Loading...
1,050,995 62 33 Loading...
1,003,569 65 32 Loading...
1,036,974 66 32 Loading...
1,490,991 67 32 Loading...
3,009,179 68 35 Loading...
1,008,595 69 35 Loading...
1,064,912 70 35 Loading...
1,998,999 75 32 Loading...
7,008,429 77 38 Loading...
1,000,689 78 39 Loading...
1,005,744 79 39 Loading...
1,007,601 80 38 Loading...
7,008,899 82 38 Loading...
9,008,299 96 48 Loading...
Number Steps Digits Resultant palindrome
(only the first 20 digits)
All 8-digit numbers Lychrel numbers: 26,792,988 (29.770%); search depth: 23,000
10,905,963 71 38 Loading...
10,069,785 72 32 Loading...
10,089,342 73 32 Loading...
11,979,990 74 32 Loading...
10,029,372 76 39 Loading...
10,029,826 81 38 Loading...
16,207,990 83 38 Loading...
90,000,589 94 48 Loading...
10,309,988 95 48 Loading...
Number Steps Digits Resultant palindrome
(only the first 20 digits)
All 9-digit numbers Lychrel numbers: 355,034,175 (39.448%); search depth: 23,000
100,389,898 84 45 Loading...
100,055,896 85 41 Loading...
110,909,992 86 40 Loading...
160,009,490 87 40 Loading...
800,067,199 88 46 Loading...
151,033,997 89 46 Loading...
100,093,573 90 46 Loading...
103,249,931 91 46 Loading...
107,025,910 92 46 Loading...
180,005,498 93 48 Loading...
100,239,862 97 52 Loading...
140,669,390 98 52 Loading...
Number Steps Digits Resultant palindrome
(only the first 20 digits)
All 10-digit numbers Lychrel numbers: 48.321%; search depth: 23,000
1,090,001,921 99 46 Loading...
7,007,009,909 100 49 Loading...
1,009,049,407 101 49 Loading...
9,000,046,899 103 49 Loading...
1,050,027,948 104 49 Loading...
1,304,199,693 105 49 Loading...
5,020,089,949 108 53 Loading...
1,005,499,526 109 53 Loading...
Number Steps Digits Resultant palindrome
(only the first 20 digits) (only the first digits)
All 11-digit numbers Lychrel numbers: 57.035%; search depth: 23,000
10,000,505,448 102 49 Loading...
10,000,922,347 106 50 Loading...
10,000,696,511 107 56 Loading...
10,701,592,943 110 53 Loading...
10,018,999,583 111 56 Loading...
10,000,442,119 112 56 Loading...
10,000,761,554 113 56 Loading...
10,084,899,970 114 56 Loading...
10,006,198,250 115 56 Loading...
18,060,009,890 116 56 Loading...
11,400,245,996 117 56 Loading...
16,002,897,892 118 56 Loading...
18,317,699,990 119 56 Loading...
37,000,488,999 122 58 Loading...
10,050,289,485 123 58 Loading...
90,000,626,389 130 65 Loading...
10,000,853,648 131 65 Loading...
13,003,696,093 132 65 Loading...
10,050,859,271 133 65 Loading...
10,287,799,930 134 65 Loading...
10,000,973,037 135 71 Loading...
10,600,713,933 136 71 Loading...
10,942,399,911 137 71 Loading...
60,000,180,709 144 66 Loading...
11,009,599,796 145 66 Loading...
16,000,097,392 146 66 Loading...
10,031,199,494 147 66 Loading...
10,306,095,991 148 66 Loading...
10,087,799,570 149 66 Loading...
Number Steps Digits Resultant palindrome
(only the first 20 digits) (only the first digits)
All 12-digit numbers Lychrel numbers: 64.527%; search depth: 23,000
100,900,509,906 120 58 Loading...
100,000,055,859 121 58 Loading...
104,000,146,950 124 58 Loading...
180,005,998,298 129 65 Loading...
300,000,185,539 142 66 Loading...
100,001,987,765 143 66 Loading...
Number Steps Digits Resultant palindrome
(only the first 20 digits) (only the first digits)
All 13-digit numbers Lychrel numbers: 71.085%; search depth: 2,500
1,000,007,614,641 125 65 Loading...
1,000,043,902,320 126 65 Loading...
1,000,006,653,746 127 65 Loading...
1,000,005,469,548 128 68 Loading...
4,000,096,953,659 139 66 Loading...
1,332,003,929,995 140 66 Loading...
1,000,201,995,662 141 66 Loading...
6,000,008,476,379 183 87 Loading...
1,200,004,031,698 184 87 Loading...
1,631,002,019,993 185 87 Loading...
1,000,006,412,206 186 87 Loading...
1,090,604,591,930 187 87 Loading...
1,600,005,969,190 188 87 Loading...
Number Steps Digits Resultant palindrome
(only the first 20 digits) (only the first digits)
All 14-digit numbers Lychrel numbers: 76.515%; search depth: 2,500
10,090,899,969,901 138 70 Loading...
40,000,004,480,279 181 87 Loading...
14,104,229,999,995 182 87 Loading...
Number Steps Digits Resultant palindrome
(only the first 20 digits) (only the first digits)
All 15-digit numbers Lychrel numbers: 81.029%; search depth: 650
100,000,109,584,608 150 80 Loading...
100,000,098,743,648 151 73 Loading...
100,004,789,906,151 152 80 Loading...
100,079,239,995,161 153 73 Loading...
100,389,619,999,030 154 73 Loading...
200,000,729,975,309 155 77 Loading...
107,045,067,996,994 156 77 Loading...
105,420,999,199,982 157 83 Loading...
101,000,269,830,970 158 77 Loading...
104,000,047,066,970 159 83 Loading...
700,000,001,839,569 163 78 Loading...
100,000,050,469,737 164 78 Loading...
101,000,789,812,993 165 77 Loading...
100,907,098,999,571 166 77 Loading...
100,017,449,991,820 167 77 Loading...
890,000,023,937,399 169 80 Loading...
100,009,989,989,199 170 76 Loading...
101,507,024,989,944 171 76 Loading...
107,405,139,999,943 172 82 Loading...
100,057,569,996,821 173 82 Loading...
103,500,369,729,970 174 80 Loading...
900,000,076,152,049 178 87 Loading...
100,000,439,071,028 179 87 Loading...
120,000,046,510,993 180 87 Loading...
103,000,015,331,997 189 87 Loading...
100,617,081,999,573 190 87 Loading...
100,009,029,910,821 191 87 Loading...
107,000,020,928,910 192 87 Loading...
100,000,090,745,299 198 92 Loading...
102,000,149,322,944 199 92 Loading...
130,000,074,931,591 200 92 Loading...
100,120,849,299,260 201 92 Loading...
Number Steps Digits Resultant palindrome
(only the first 20 digits) (only the first digits)
All 16-digit numbers Lychrel numbers: 84.763%; search depth: 650
6,000,000,039,361,479 161 78 Loading...
1,421,000,069,679,996 162 78 Loading...
1,000,650,998,992,311 168 76 Loading...
1,000,002,899,436,401 175 78 Loading...
1,000,100,396,492,200 176 78 Loading...
1,400,000,027,672,498 177 87 Loading...
7,090,000,039,309,919 193 92 Loading...
1,000,050,048,994,957 194 92 Loading...
1,003,000,024,749,923 195 92 Loading...
1,000,803,019,495,711 196 92 Loading...
1,030,020,097,997,900 197 92 Loading...
Number Steps Digits Resultant palindrome
(only the first 20 digits) (only the first digits)
All 17-digit numbers Lychrel numbers: 87.768%; search depth: 650
10,000,000,730,931,027 160 82 Loading...
20,005,000,862,599,819 206 90 Loading...
11,450,360,479,969,994 207 90 Loading...
10,009,000,275,899,569 208 90 Loading...
10,059,430,139,999,234 209 90 Loading...
12,179,702,595,999,991 210 90 Loading...
79,000,000,445,783,599 229 112 Loading...
10,000,000,767,846,797 230 112 Loading...
10,000,000,673,402,336 231 111 Loading...
10,000,000,525,586,206 232 111 Loading...
10,005,000,760,994,249 233 111 Loading...
10,030,503,899,969,524 234 111 Loading...
12,000,009,694,736,291 235 111 Loading...
10,442,000,392,399,960 236 111 Loading...
Number Steps Digits Resultant palindrome
(only the first 20 digits) (only the first digits)
All 18-digit numbers Lychrel numbers: 90.241%; search depth: 650
195,030,047,999,791,993 202 105 Loading...
100,000,078,999,111,766 203 105 Loading...
100,710,000,333,399,973 204 90 Loading...
100,000,002,973,751,552 205 90 Loading...
100,000,277,999,334,202 211 107 Loading...
110,300,361,999,869,090 212 107 Loading...
300,000,000,128,545,799 213 101 Loading...
104,300,000,514,769,945 214 101 Loading...
100,700,000,509,609,622 215 101 Loading...
120,906,490,499,909,290 216 101 Loading...
900,040,000,881,499,569 218 103 Loading...
100,072,100,489,999,238 219 103 Loading...
121,506,542,999,979,993 220 103 Loading...
106,096,507,979,997,951 221 103 Loading...
100,980,800,839,699,830 222 103 Loading...
600,000,000,606,339,049 227 112 Loading...
170,500,000,303,619,996 228 112 Loading...
Number Steps Digits Resultant palindrome
(only the first 20 digits) (only the first digits)
All 19-digit numbers Lychrel numbers: 92.181%; search depth: 650
1,000,000,038,990,407,538 217 107 Loading...
9,000,000,000,255,353,839 224 111 Loading...
1,000,000,005,577,676,468 225 111 Loading...
1,060,000,000,523,124,995 226 112 Loading...
3,000,000,022,999,288,679 258 119 Loading...
1,000,000,079,994,144,385 259 119 Loading...
1,003,062,289,999,939,142 260 119 Loading...
1,186,060,307,891,929,990 261 119 Loading...
Number Steps Digits Resultant palindrome
(only the first 20 digits) (only the first digits)
All 20-digit numbers Lychrel numbers: 93.789%; search depth: 335
10,000,000,039,513,841,287 223 112 Loading...
70,000,000,000,507,277,299 253 119 Loading...
10,200,000,000,708,183,947 254 119 Loading...
10,022,000,904,998,799,523 255 119 Loading...
10,000,000,039,395,795,416 256 119 Loading...
10,200,000,000,065,287,900 257 119 Loading...
Number Steps Digits Resultant palindrome
(only the first 20 digits) (only the first digits)
All 21-digit numbers Lychrel numbers: 95.026%; search depth: 350
500,000,060,001,199,990,549 251 119 Loading...
100,000,081,000,999,940,726 252 119 Loading...
Number Steps Digits Resultant palindrome
(only the first 20 digits) (only the first digits)
All 22-digit numbers Lychrel numbers: 96.059%; search depth: 365
3,000,800,040,089,968,999,539 238 120 Loading...
1,000,950,870,044,993,999,265 239 120 Loading...
1,000,000,040,796,912,297,132 240 120 Loading...
1,990,000,200,024,599,902,999 249 119 Loading...
1,000,000,630,016,999,401,994 250 119 Loading...
Number Steps Digits Resultant palindrome
(only the first 20 digits) (only the first digits)
23-digit numbers Range is being tested; search depth: 375
CND 10,010,020,600,686,999,559,662 237 120 Loading...
CND 10,108,000,002,095,990,099,950 241 125 Loading...
CND 10,060,300,040,069,783,909,870 242 106 Loading...
CND 10,807,308,105,195,993,997,970 243 128 Loading...
CND 30,000,000,000,837,077,247,379 245 119 Loading...
10,000,000,000,500,075,338,778 246 112 Loading...
10,000,000,380,589,999,534,342 247 119 Loading...
CND 10,385,810,003,399,979,999,951 248 112 Loading...
CND 15,007,060,502,692,999,894,096 262 134 Loading...
10,000,006,000,090,499,474,959 286 142 Loading...
10,000,008,700,094,994,282,974 287 142 Loading...
CND 12,000,700,000,025,339,936,491 288 142 Loading...
CND 10,036,069,400,174,999,499,950 289 142 Loading...
Number Steps Digits Resultant palindrome
(only the first 20 digits) (only the first digits)
24-digit numbers Range is being tested; search depth: 395
CND 111,120,050,000,380,599,699,992 244 119 Loading...
CND 700,000,000,000,668,930,560,769 267 127 Loading...
CND 100,000,000,008,974,960,730,837 268 127 Loading...
CND 102,516,500,000,669,459,999,913 269 127 Loading...
CND 106,758,031,110,599,996,999,901 270 127 Loading...
CND 100,100,020,010,790,098,449,800 271 127 Loading...
CND 100,000,000,069,999,589,985,049 282 142 Loading...
CND 100,000,000,089,999,249,947,024 283 142 Loading...
CND 140,000,030,099,999,099,448,991 284 142 Loading...
CND 100,500,000,199,999,537,709,960 285 142 Loading...
Number Steps Digits Resultant palindrome
(only the first 20 digits) (only the first digits)
25-digit numbers Range is being tested; search depth: 410
CND 1,010,000,000,019,912,549,260,950 263 128 Loading...
CND 6,000,000,000,003,126,663,605,379 265 127 Loading...
CND 1,420,000,000,004,713,336,302,996 266 127 Loading...
CND 1,000,000,049,003,739,995,755,649 272 130 Loading...
CND 1,000,000,079,641,999,992,877,324 273 130 Loading...
CND 1,040,200,620,332,990,995,192,950 274 127 Loading...
CND 1,011,050,517,536,999,997,929,950 275 130 Loading...
CND 1,000,000,000,008,771,050,441,908 276 142 Loading...
CND 1,100,000,000,004,165,700,220,993 277 142 Loading...
CND 1,000,000,000,008,037,782,836,719 278 142 Loading...
CND 1,000,000,000,009,468,449,423,854 279 142 Loading...
CND 1,000,004,285,088,999,999,687,280 280 142 Loading...
CND 1,000,000,000,007,468,472,243,350 281 142 Loading...
CND 1,000,000,009,001,899,177,117,039 290 132 Loading...
CND 1,000,000,000,008,799,678,139,630 291 132 Loading...
CND 1,000,000,000,005,083,294,994,790 292 132 Loading...
CND 1,000,206,827,388,999,999,095,750 293 132 Loading...
Number Steps Digits Resultant palindrome
(only the first 20 digits) (only the first digits)
26-digit numbers Range is being tested; search depth: 420
CND 10,000,013,142,009,999,999,998,117 264 130 Loading...