Compare 247 vs 251
| Property | 247 | 251 |
|---|---|---|
| Type | semiprime | prime |
| Unique factors | 2 | 1 |
| Total factors | 2 | 1 |
| Prime factorization | 131 × 191 | 2511 |
| Prime factorization | 13 × 19 | 251 |
| Divisors count | 4 | 2 |
| Divisors | 1, 13, 19, 247 | 1, 251 |
| Number of properties | 1 | 10 |
| Chen primes | 41st | |
| Good primes | 19th | |
| Harmonic primes | 20th | |
| Isolated primes | 21st | |
| Primes | 54th | |
| Semiprimes | 79th | |
| Sexy primes (1st member) | 30th | |
| Sexy prime quadrupletss (1st member) | 5th | |
| Sexy prime triplets (1st member) | 15th | |
| Solinas primes | 30th | |
| Sophie germain primes | 18th | |
| Roman numberals | CCXLVII | CCLI |
| Base 2 | 111101112 | 111110112 |
| Base 3 | 1000113 | 1000223 |
| Base 4 | 33134 | 33234 |
| Base 5 | 14425 | 20015 |
| Base 6 | 10516 | 10556 |
| Base 7 | 5027 | 5067 |
| Base 8 | 3678 | 3738 |
| Base 9 | 3049 | 3089 |
| Base 10 | 24710 | 25110 |
| Base 11 | 20511 | 20911 |
| Base 12 | 18712 | 18b12 |
| Base 13 | 16013 | 16413 |
| Base 14 | 13914 | 13d14 |
| Base 15 | 11715 | 11b15 |
| Base 16 | f716 | fb16 |