Compare 991 vs 1231
| Property | 991 | 1231 |
|---|---|---|
| Type | prime | prime |
| Unique factors | 1 | 1 |
| Total factors | 1 | 1 |
| Prime factorization | 9911 | 12311 |
| Prime factorization | 991 | 1231 |
| Divisors count | 2 | 2 |
| Divisors | 1, 991 | 1, 1231 |
| Number of properties | 10 | 6 |
| Additive primes | 89th | 108th |
| Chen primes | 115th | |
| Emirps | 36th | 56th |
| Isolated primes | 98th | |
| Lucky primes | 42nd | 52nd |
| Primes | 167th | 202nd |
| Sexy primes (1st member) | 74th | 88th |
| Solinas primes | 43rd | |
| Super primes | 39th | |
| Twin primes (2nd member) | 42nd | |
| Ulam primes | 18th | |
| Roman numberals | CMXCI | MCCXXXI |
| Base 2 | 11110111112 | 100110011112 |
| Base 3 | 11002013 | 12001213 |
| Base 4 | 331334 | 1030334 |
| Base 5 | 124315 | 144115 |
| Base 6 | 43316 | 54116 |
| Base 7 | 26147 | 34067 |
| Base 8 | 17378 | 23178 |
| Base 9 | 13219 | 16179 |
| Base 10 | 99110 | 123110 |
| Base 11 | 82111 | a1a11 |
| Base 12 | 6a712 | 86712 |
| Base 13 | 5b313 | 73913 |
| Base 14 | 50b14 | 63d14 |
| Base 15 | 46115 | 57115 |
| Base 16 | 3df16 | 4cf16 |