Compare 643 vs 655
| Property | 643 | 655 |
|---|---|---|
| Type | prime | semiprime |
| Unique factors | 1 | 2 |
| Total factors | 1 | 2 |
| Prime factorization | 6431 | 51 × 1311 |
| Prime factorization | 643 | 5 × 131 |
| Divisors count | 2 | 4 |
| Divisors | 1, 643 | 1, 5, 131, 655 |
| Number of properties | 7 | 1 |
| Additive primes | 63rd | |
| Cousin primes (1st member) | 29th | |
| Left-truncatable primes | 38th | |
| Lucky primes | 33rd | |
| Primes | 117th | |
| Prime triplets (2nd member) | 24th | |
| Semiprimes | 197th | |
| Twin primes (2nd member) | 29th | |
| Roman numberals | DCXLIII | DCLV |
| Base 2 | 10100000112 | 10100011112 |
| Base 3 | 2122113 | 2200213 |
| Base 4 | 220034 | 220334 |
| Base 5 | 100335 | 101105 |
| Base 6 | 25516 | 30116 |
| Base 7 | 16067 | 16247 |
| Base 8 | 12038 | 12178 |
| Base 9 | 7849 | 8079 |
| Base 10 | 64310 | 65510 |
| Base 11 | 53511 | 54611 |
| Base 12 | 45712 | 46712 |
| Base 13 | 3a613 | 3b513 |
| Base 14 | 33d14 | 34b14 |
| Base 15 | 2cd15 | 2da15 |
| Base 16 | 28316 | 28f16 |