Compare 245 vs 251
| Property | 245 | 251 |
|---|---|---|
| Type | composite number | prime |
| Unique factors | 2 | 1 |
| Total factors | 3 | 1 |
| Prime factorization | 51 × 72 | 2511 |
| Prime factorization | 5 × 7 × 7 | 251 |
| Divisors count | 6 | 2 |
| Divisors | 1, 5, 7, 35, 49, 245 | 1, 251 |
| Number of properties | 0 | 10 |
| Chen primes | 41st | |
| Good primes | 19th | |
| Harmonic primes | 20th | |
| Isolated primes | 21st | |
| Primes | 54th | |
| Sexy primes (1st member) | 30th | |
| Sexy prime quadrupletss (1st member) | 5th | |
| Sexy prime triplets (1st member) | 15th | |
| Solinas primes | 30th | |
| Sophie germain primes | 18th | |
| Roman numberals | CCXLV | CCLI |
| Base 2 | 111101012 | 111110112 |
| Base 3 | 1000023 | 1000223 |
| Base 4 | 33114 | 33234 |
| Base 5 | 14405 | 20015 |
| Base 6 | 10456 | 10556 |
| Base 7 | 5007 | 5067 |
| Base 8 | 3658 | 3738 |
| Base 9 | 3029 | 3089 |
| Base 10 | 24510 | 25110 |
| Base 11 | 20311 | 20911 |
| Base 12 | 18512 | 18b12 |
| Base 13 | 15b13 | 16413 |
| Base 14 | 13714 | 13d14 |
| Base 15 | 11515 | 11b15 |
| Base 16 | f516 | fb16 |