Compare 21991 vs 21999
| Property | 21991 | 21999 |
|---|---|---|
| Type | prime | semiprime |
| Unique factors | 1 | 2 |
| Total factors | 1 | 2 |
| Prime factorization | 219911 | 31 × 73331 |
| Prime factorization | 21991 | 3 × 7333 |
| Divisors count | 2 | 4 |
| Divisors | 1, 21991 | 1, 3, 7333, 21999 |
| Number of properties | 5 | 1 |
| Chen primes | 1208th | |
| Isolated primes | 1720th | |
| Primes | 2463rd | |
| Semiprimes | 5554th | |
| Sexy primes (1st member) | 742nd | |
| Sexy prime triplets (1st member) | 202nd | |
| Roman numberals | ||
| Base 2 | 1010101111001112 | 1010101111011112 |
| Base 3 | 10100111113 | 10100112103 |
| Base 4 | 111132134 | 111132334 |
| Base 5 | 12004315 | 12004445 |
| Base 6 | 2454516 | 2455036 |
| Base 7 | 1210547 | 1210657 |
| Base 8 | 527478 | 527578 |
| Base 9 | 331449 | 331539 |
| Base 10 | 2199110 | 2199910 |
| Base 11 | 1558211 | 1558a11 |
| Base 12 | 1088712 | 1089312 |
| Base 13 | a01813 | a02313 |
| Base 14 | 802b14 | 803514 |
| Base 15 | 67b115 | 67b915 |
| Base 16 | 55e716 | 55ef16 |