Compare 21 vs 42
| Property | 21 | 42 |
|---|---|---|
| Type | semiprime | composite number |
| Unique factors | 2 | 3 |
| Total factors | 2 | 3 |
| Prime factorization | 31 × 71 | 21 × 31 × 71 |
| Prime factorization | 3 × 7 | 2 × 3 × 7 |
| Divisors count | 4 | 8 |
| Divisors | 1, 3, 7, 21 | 1, 2, 3, 6, 7, 14, 21, 42 |
| Number of properties | 1 | 0 |
| Semiprimes | 7th | |
| Roman numberals | XXI | XLII |
| Base 2 | 101012 | 1010102 |
| Base 3 | 2103 | 11203 |
| Base 4 | 1114 | 2224 |
| Base 5 | 415 | 1325 |
| Base 6 | 336 | 1106 |
| Base 7 | 307 | 607 |
| Base 8 | 258 | 528 |
| Base 9 | 239 | 469 |
| Base 10 | 2110 | 4210 |
| Base 11 | 1a11 | 3911 |
| Base 12 | 1912 | 3612 |
| Base 13 | 1813 | 3313 |
| Base 14 | 1714 | 3014 |
| Base 15 | 1615 | 2c15 |
| Base 16 | 1516 | 2a16 |