Compare 521 vs 991
| Property | 521 | 991 |
|---|---|---|
| Type | prime | prime |
| Unique factors | 1 | 1 |
| Total factors | 1 | 1 |
| Prime factorization | 5211 | 9911 |
| Prime factorization | 521 | 991 |
| Divisors count | 2 | 2 |
| Divisors | 1, 521 | 1, 991 |
| Number of properties | 6 | 10 |
| Additive primes | 89th | |
| Chen primes | 70th | 115th |
| Emirps | 36th | |
| Isolated primes | 98th | |
| Lucas primes | 8th | |
| Lucky primes | 42nd | |
| Primes | 98th | 167th |
| Pythagorean primes | 46th | |
| Sexy primes (1st member) | 74th | |
| Solinas primes | 39th | 43rd |
| Super primes | 39th | |
| Twin primes (1st member) | 25th | |
| Ulam primes | 18th | |
| Roman numberals | DXXI | CMXCI |
| Base 2 | 10000010012 | 11110111112 |
| Base 3 | 2010223 | 11002013 |
| Base 4 | 200214 | 331334 |
| Base 5 | 40415 | 124315 |
| Base 6 | 22256 | 43316 |
| Base 7 | 13437 | 26147 |
| Base 8 | 10118 | 17378 |
| Base 9 | 6389 | 13219 |
| Base 10 | 52110 | 99110 |
| Base 11 | 43411 | 82111 |
| Base 12 | 37512 | 6a712 |
| Base 13 | 31113 | 5b313 |
| Base 14 | 29314 | 50b14 |
| Base 15 | 24b15 | 46115 |
| Base 16 | 20916 | 3df16 |