Compare 31 vs 199
| Property | 31 | 199 |
|---|---|---|
| Type | prime | prime |
| Unique factors | 1 | 1 |
| Total factors | 1 | 1 |
| Prime factorization | 311 | 1991 |
| Prime factorization | 31 | 199 |
| Divisors count | 2 | 2 |
| Divisors | 1, 31 | 1, 199 |
| Number of properties | 18 | 10 |
| Additive primes | 27th | |
| Centered decagonal primes | 2nd | |
| Centered triangular primes | 2nd | 4th |
| Chen primes | 11th | 36th |
| Class 1+ primes | 8th | |
| Emirps | 3rd | 15th |
| Euclid primes | 4th | |
| Happy primes | 5th | |
| Lucas primes | 7th | |
| Lucky primes | 4th | |
| Mersenne primes | 3rd | |
| Multiplicative primes | 7th | |
| Pierpont primes of the 2nd kind | 8th | |
| Primes | 11th | 46th |
| Prime quadruplets (4th member) | 4th | |
| Prime triplets (3rd member) | 14th | |
| Right-truncatable primes | 7th | |
| Sexy primes (1st member) | 7th | |
| Sexy primes (2nd member) | 26th | |
| Sexy prime triplets (1st member) | 5th | |
| Solinas primes | 10th | |
| Super primes | 5th | |
| Twin primes (2nd member) | 5th | 15th |
| Roman numberals | XXXI | CXCIX |
| Base 2 | 111112 | 110001112 |
| Base 3 | 10113 | 211013 |
| Base 4 | 1334 | 30134 |
| Base 5 | 1115 | 12445 |
| Base 6 | 516 | 5316 |
| Base 7 | 437 | 4037 |
| Base 8 | 378 | 3078 |
| Base 9 | 349 | 2419 |
| Base 10 | 3110 | 19910 |
| Base 11 | 2911 | 17111 |
| Base 12 | 2712 | 14712 |
| Base 13 | 2513 | 12413 |
| Base 14 | 2314 | 10314 |
| Base 15 | 2115 | d415 |
| Base 16 | 1f16 | c716 |