Compare 991 vs 1009
| Property | 991 | 1009 |
|---|---|---|
| Type | prime | prime |
| Unique factors | 1 | 1 |
| Total factors | 1 | 1 |
| Prime factorization | 9911 | 10091 |
| Prime factorization | 991 | 1009 |
| Divisors count | 2 | 2 |
| Divisors | 1, 991 | 1, 1009 |
| Number of properties | 10 | 10 |
| Additive primes | 89th | |
| Chen primes | 115th | 116th |
| Cousin primes (1st member) | 42nd | |
| Emirps | 36th | 37th |
| Good primes | 45th | |
| Happy primes | 36th | |
| Isolated primes | 98th | 100th |
| Lucky primes | 42nd | 44th |
| Primes | 167th | 169th |
| Pythagorean primes | 81st | |
| Sexy primes (1st member) | 74th | |
| Solinas primes | 43rd | 44th |
| Super primes | 39th | |
| Ulam primes | 18th | |
| Roman numberals | CMXCI | MIX |
| Base 2 | 11110111112 | 11111100012 |
| Base 3 | 11002013 | 11011013 |
| Base 4 | 331334 | 333014 |
| Base 5 | 124315 | 130145 |
| Base 6 | 43316 | 44016 |
| Base 7 | 26147 | 26417 |
| Base 8 | 17378 | 17618 |
| Base 9 | 13219 | 13419 |
| Base 10 | 99110 | 100910 |
| Base 11 | 82111 | 83811 |
| Base 12 | 6a712 | 70112 |
| Base 13 | 5b313 | 5c813 |
| Base 14 | 50b14 | 52114 |
| Base 15 | 46115 | 47415 |
| Base 16 | 3df16 | 3f116 |