Compare 991 vs 1531
| Property | 991 | 1531 |
|---|---|---|
| Type | prime | prime |
| Unique factors | 1 | 1 |
| Total factors | 1 | 1 |
| Prime factorization | 9911 | 15311 |
| Prime factorization | 991 | 1531 |
| Divisors count | 2 | 2 |
| Divisors | 1, 991 | 1, 1531 |
| Number of properties | 10 | 5 |
| Additive primes | 89th | |
| Centered decagonal primes | 13th | |
| Chen primes | 115th | |
| Emirps | 36th | |
| Isolated primes | 98th | 143rd |
| Long primes | 91st | |
| Lucky primes | 42nd | |
| Primes | 167th | 242nd |
| Sexy primes (1st member) | 74th | |
| Solinas primes | 43rd | |
| Super primes | 39th | |
| Ulam primes | 18th | 22nd |
| Roman numberals | CMXCI | MDXXXI |
| Base 2 | 11110111112 | 101111110112 |
| Base 3 | 11002013 | 20022013 |
| Base 4 | 331334 | 1133234 |
| Base 5 | 124315 | 221115 |
| Base 6 | 43316 | 110316 |
| Base 7 | 26147 | 43157 |
| Base 8 | 17378 | 27738 |
| Base 9 | 13219 | 20819 |
| Base 10 | 99110 | 153110 |
| Base 11 | 82111 | 117211 |
| Base 12 | 6a712 | a7712 |
| Base 13 | 5b313 | 90a13 |
| Base 14 | 50b14 | 7b514 |
| Base 15 | 46115 | 6c115 |
| Base 16 | 3df16 | 5fb16 |