Compare 1561 vs 1571
| Property | 1561 | 1571 |
|---|---|---|
| Type | semiprime | prime |
| Unique factors | 2 | 1 |
| Total factors | 2 | 1 |
| Prime factorization | 71 × 2231 | 15711 |
| Prime factorization | 7 × 223 | 1571 |
| Divisors count | 4 | 2 |
| Divisors | 1, 7, 223, 1561 | 1, 1571 |
| Number of properties | 1 | 4 |
| Cousin primes (2nd member) | 55th | |
| Isolated primes | 149th | |
| Long primes | 96th | |
| Primes | 248th | |
| Semiprimes | 453rd | |
| Roman numberals | MDLXI | MDLXXI |
| Base 2 | 110000110012 | 110001000112 |
| Base 3 | 20102113 | 20110123 |
| Base 4 | 1201214 | 1202034 |
| Base 5 | 222215 | 222415 |
| Base 6 | 111216 | 111356 |
| Base 7 | 43607 | 44037 |
| Base 8 | 30318 | 30438 |
| Base 9 | 21249 | 21359 |
| Base 10 | 156110 | 157110 |
| Base 11 | 119a11 | 11a911 |
| Base 12 | aa112 | aab12 |
| Base 13 | 93113 | 93b13 |
| Base 14 | 7d714 | 80314 |
| Base 15 | 6e115 | 6eb15 |
| Base 16 | 61916 | 62316 |