Compare 645 vs 647
| Property | 645 | 647 |
|---|---|---|
| Type | composite number | prime |
| Unique factors | 3 | 1 |
| Total factors | 3 | 1 |
| Prime factorization | 31 × 51 × 431 | 6471 |
| Prime factorization | 3 × 5 × 43 | 647 |
| Divisors count | 8 | 2 |
| Divisors | 1, 3, 5, 15, 43, 129, 215, 645 | 1, 647 |
| Number of properties | 0 | 15 |
| Additive primes | 64th | |
| Chen primes | 82nd | |
| Class 1+ primes | 17th | |
| Cousin primes (2nd member) | 29th | |
| Isolated primes | 61st | |
| Left-truncatable primes | 39th | |
| Long primes | 43rd | |
| Pierpont primes of the 2nd kind | 17th | |
| Primes | 118th | |
| Prime triplets (3rd member) | 24th | |
| Sexy primes (1st member) | 58th | |
| Sexy primes (2nd member) | 57th | |
| Sexy prime quadrupletss (2nd member) | 7th | |
| Sexy prime triplets (1st member) | 25th | |
| Sexy prime triplets (2nd member) | 24th | |
| Roman numberals | DCXLV | DCXLVII |
| Base 2 | 10100001012 | 10100001112 |
| Base 3 | 2122203 | 2122223 |
| Base 4 | 220114 | 220134 |
| Base 5 | 100405 | 100425 |
| Base 6 | 25536 | 25556 |
| Base 7 | 16117 | 16137 |
| Base 8 | 12058 | 12078 |
| Base 9 | 7869 | 7889 |
| Base 10 | 64510 | 64710 |
| Base 11 | 53711 | 53911 |
| Base 12 | 45912 | 45b12 |
| Base 13 | 3a813 | 3aa13 |
| Base 14 | 34114 | 34314 |
| Base 15 | 2d015 | 2d215 |
| Base 16 | 28516 | 28716 |