Compare 91 vs 97
| Property | 91 | 97 |
|---|---|---|
| Type | semiprime | prime |
| Unique factors | 2 | 1 |
| Total factors | 2 | 1 |
| Prime factorization | 71 × 131 | 971 |
| Prime factorization | 7 × 13 | 97 |
| Divisors count | 4 | 2 |
| Divisors | 1, 7, 13, 91 | 1, 97 |
| Number of properties | 1 | 20 |
| Cousin primes (1st member) | 9th | |
| Emirps | 8th | |
| Good primes | 11th | |
| Happy primes | 7th | |
| Isolated primes | 10th | |
| Left-truncatable primes | 15th | |
| Long primes | 9th | |
| Pierpont primes | 10th | |
| Primes | 25th | |
| Prime quintuplet 1s (1st member) | 2nd | |
| Prime sextuplets (1st member) | 2nd | |
| Prime triplets (1st member) | 9th | |
| Proth primes | 6th | |
| Pythagorean primes | 11th | |
| Quartan primes | 3rd | |
| Semiprimes | 31st | |
| Sexy primes (1st member) | 16th | |
| Sexy prime triplets (1st member) | 10th | |
| Solinas primes | 20th | |
| Thabit primes of the 2nd kind | 3rd | |
| Ulam primes | 7th | |
| Roman numberals | XCI | XCVII |
| Base 2 | 10110112 | 11000012 |
| Base 3 | 101013 | 101213 |
| Base 4 | 11234 | 12014 |
| Base 5 | 3315 | 3425 |
| Base 6 | 2316 | 2416 |
| Base 7 | 1607 | 1667 |
| Base 8 | 1338 | 1418 |
| Base 9 | 1119 | 1179 |
| Base 10 | 9110 | 9710 |
| Base 11 | 8311 | 8911 |
| Base 12 | 7712 | 8112 |
| Base 13 | 7013 | 7613 |
| Base 14 | 6714 | 6d14 |
| Base 15 | 6115 | 6715 |
| Base 16 | 5b16 | 6116 |