Compare 655 vs 661
| Property | 655 | 661 |
|---|---|---|
| Type | semiprime | prime |
| Unique factors | 2 | 1 |
| Total factors | 2 | 1 |
| Prime factorization | 51 × 1311 | 6611 |
| Prime factorization | 5 × 131 | 661 |
| Divisors count | 4 | 2 |
| Divisors | 1, 5, 131, 655 | 1, 661 |
| Number of properties | 1 | 5 |
| Additive primes | 65th | |
| Centered decagonal primes | 8th | |
| Primes | 121st | |
| Pythagorean primes | 57th | |
| Semiprimes | 197th | |
| Twin primes (2nd member) | 30th | |
| Roman numberals | DCLV | DCLXI |
| Base 2 | 10100011112 | 10100101012 |
| Base 3 | 2200213 | 2201113 |
| Base 4 | 220334 | 221114 |
| Base 5 | 101105 | 101215 |
| Base 6 | 30116 | 30216 |
| Base 7 | 16247 | 16337 |
| Base 8 | 12178 | 12258 |
| Base 9 | 8079 | 8149 |
| Base 10 | 65510 | 66110 |
| Base 11 | 54611 | 55111 |
| Base 12 | 46712 | 47112 |
| Base 13 | 3b513 | 3bb13 |
| Base 14 | 34b14 | 35314 |
| Base 15 | 2da15 | 2e115 |
| Base 16 | 28f16 | 29516 |