Compare 21 vs 30
| Property | 21 | 30 |
|---|---|---|
| Type | semiprime | composite number |
| Unique factors | 2 | 3 |
| Total factors | 2 | 3 |
| Prime factorization | 31 × 71 | 21 × 31 × 51 |
| Prime factorization | 3 × 7 | 2 × 3 × 5 |
| Divisors count | 4 | 8 |
| Divisors | 1, 3, 7, 21 | 1, 2, 3, 5, 6, 10, 15, 30 |
| Number of properties | 1 | 0 |
| Semiprimes | 7th | |
| Roman numberals | XXI | XXX |
| Base 2 | 101012 | 111102 |
| Base 3 | 2103 | 10103 |
| Base 4 | 1114 | 1324 |
| Base 5 | 415 | 1105 |
| Base 6 | 336 | 506 |
| Base 7 | 307 | 427 |
| Base 8 | 258 | 368 |
| Base 9 | 239 | 339 |
| Base 10 | 2110 | 3010 |
| Base 11 | 1a11 | 2811 |
| Base 12 | 1912 | 2612 |
| Base 13 | 1813 | 2413 |
| Base 14 | 1714 | 2214 |
| Base 15 | 1615 | 2015 |
| Base 16 | 1516 | 1e16 |