Compare 521 vs 661
| Property | 521 | 661 |
|---|---|---|
| Type | prime | prime |
| Unique factors | 1 | 1 |
| Total factors | 1 | 1 |
| Prime factorization | 5211 | 6611 |
| Prime factorization | 521 | 661 |
| Divisors count | 2 | 2 |
| Divisors | 1, 521 | 1, 661 |
| Number of properties | 6 | 5 |
| Additive primes | 65th | |
| Centered decagonal primes | 8th | |
| Chen primes | 70th | |
| Lucas primes | 8th | |
| Primes | 98th | 121st |
| Pythagorean primes | 46th | 57th |
| Solinas primes | 39th | |
| Twin primes (1st member) | 25th | |
| Twin primes (2nd member) | 30th | |
| Roman numberals | DXXI | DCLXI |
| Base 2 | 10000010012 | 10100101012 |
| Base 3 | 2010223 | 2201113 |
| Base 4 | 200214 | 221114 |
| Base 5 | 40415 | 101215 |
| Base 6 | 22256 | 30216 |
| Base 7 | 13437 | 16337 |
| Base 8 | 10118 | 12258 |
| Base 9 | 6389 | 8149 |
| Base 10 | 52110 | 66110 |
| Base 11 | 43411 | 55111 |
| Base 12 | 37512 | 47112 |
| Base 13 | 31113 | 3bb13 |
| Base 14 | 29314 | 35314 |
| Base 15 | 24b15 | 2e115 |
| Base 16 | 20916 | 29516 |