Compare 661 vs 751
| Property | 661 | 751 |
|---|---|---|
| Type | prime | prime |
| Unique factors | 1 | 1 |
| Total factors | 1 | 1 |
| Prime factorization | 6611 | 7511 |
| Prime factorization | 661 | 751 |
| Divisors count | 2 | 2 |
| Divisors | 1, 661 | 1, 751 |
| Number of properties | 5 | 7 |
| Additive primes | 65th | 70th |
| Centered decagonal primes | 8th | |
| Chen primes | 90th | |
| Emirps | 26th | |
| Isolated primes | 74th | |
| Primes | 121st | 133rd |
| Pythagorean primes | 57th | |
| Sexy primes (1st member) | 63rd | |
| Twin primes (2nd member) | 30th | |
| Ulam primes | 16th | |
| Roman numberals | DCLXI | DCCLI |
| Base 2 | 10100101012 | 10111011112 |
| Base 3 | 2201113 | 10002113 |
| Base 4 | 221114 | 232334 |
| Base 5 | 101215 | 110015 |
| Base 6 | 30216 | 32516 |
| Base 7 | 16337 | 21227 |
| Base 8 | 12258 | 13578 |
| Base 9 | 8149 | 10249 |
| Base 10 | 66110 | 75110 |
| Base 11 | 55111 | 62311 |
| Base 12 | 47112 | 52712 |
| Base 13 | 3bb13 | 45a13 |
| Base 14 | 35314 | 3b914 |
| Base 15 | 2e115 | 35115 |
| Base 16 | 29516 | 2ef16 |