Compare 661 vs 2531
| Property | 661 | 2531 |
|---|---|---|
| Type | prime | prime |
| Unique factors | 1 | 1 |
| Total factors | 1 | 1 |
| Prime factorization | 6611 | 25311 |
| Prime factorization | 661 | 2531 |
| Divisors count | 2 | 2 |
| Divisors | 1, 661 | 1, 2531 |
| Number of properties | 5 | 7 |
| Additive primes | 65th | 193rd |
| Centered decagonal primes | 8th | 16th |
| Chen primes | 223rd | |
| Good primes | 72nd | |
| Harmonic primes | 139th | |
| Isolated primes | 227th | |
| Primes | 121st | 370th |
| Pythagorean primes | 57th | |
| Twin primes (2nd member) | 30th | |
| Roman numberals | DCLXI | MMDXXXI |
| Base 2 | 10100101012 | 1001111000112 |
| Base 3 | 2201113 | 101102023 |
| Base 4 | 221114 | 2132034 |
| Base 5 | 101215 | 401115 |
| Base 6 | 30216 | 154156 |
| Base 7 | 16337 | 102447 |
| Base 8 | 12258 | 47438 |
| Base 9 | 8149 | 34229 |
| Base 10 | 66110 | 253110 |
| Base 11 | 55111 | 19a111 |
| Base 12 | 47112 | 156b12 |
| Base 13 | 3bb13 | 11c913 |
| Base 14 | 35314 | ccb14 |
| Base 15 | 2e115 | b3b15 |
| Base 16 | 29516 | 9e316 |