Compare 991 vs 1721
| Property | 991 | 1721 |
|---|---|---|
| Type | prime | prime |
| Unique factors | 1 | 1 |
| Total factors | 1 | 1 |
| Prime factorization | 9911 | 17211 |
| Prime factorization | 991 | 1721 |
| Divisors count | 2 | 2 |
| Divisors | 1, 991 | 1, 1721 |
| Number of properties | 10 | 6 |
| Additive primes | 89th | 143rd |
| Chen primes | 115th | 169th |
| Emirps | 36th | |
| Isolated primes | 98th | |
| Lucky primes | 42nd | |
| Primes | 167th | 268th |
| Pythagorean primes | 130th | |
| Sexy primes (1st member) | 74th | |
| Solinas primes | 43rd | |
| Super primes | 39th | |
| Twin primes (1st member) | 55th | |
| Ulam primes | 18th | 25th |
| Roman numberals | CMXCI | MDCCXXI |
| Base 2 | 11110111112 | 110101110012 |
| Base 3 | 11002013 | 21002023 |
| Base 4 | 331334 | 1223214 |
| Base 5 | 124315 | 233415 |
| Base 6 | 43316 | 115456 |
| Base 7 | 26147 | 50067 |
| Base 8 | 17378 | 32718 |
| Base 9 | 13219 | 23229 |
| Base 10 | 99110 | 172110 |
| Base 11 | 82111 | 132511 |
| Base 12 | 6a712 | bb512 |
| Base 13 | 5b313 | a2513 |
| Base 14 | 50b14 | 8ad14 |
| Base 15 | 46115 | 79b15 |
| Base 16 | 3df16 | 6b916 |