Compare 21 vs 45
| Property | 21 | 45 |
|---|---|---|
| Type | semiprime | composite number |
| Unique factors | 2 | 2 |
| Total factors | 2 | 3 |
| Prime factorization | 31 × 71 | 32 × 51 |
| Prime factorization | 3 × 7 | 3 × 3 × 5 |
| Divisors count | 4 | 6 |
| Divisors | 1, 3, 7, 21 | 1, 3, 5, 9, 15, 45 |
| Number of properties | 1 | 0 |
| Semiprimes | 7th | |
| Roman numberals | XXI | XLV |
| Base 2 | 101012 | 1011012 |
| Base 3 | 2103 | 12003 |
| Base 4 | 1114 | 2314 |
| Base 5 | 415 | 1405 |
| Base 6 | 336 | 1136 |
| Base 7 | 307 | 637 |
| Base 8 | 258 | 558 |
| Base 9 | 239 | 509 |
| Base 10 | 2110 | 4510 |
| Base 11 | 1a11 | 4111 |
| Base 12 | 1912 | 3912 |
| Base 13 | 1813 | 3613 |
| Base 14 | 1714 | 3314 |
| Base 15 | 1615 | 3015 |
| Base 16 | 1516 | 2d16 |