Compare 21 vs 55
| Property | 21 | 55 |
|---|---|---|
| Type | semiprime | semiprime |
| Unique factors | 2 | 2 |
| Total factors | 2 | 2 |
| Prime factorization | 31 × 71 | 51 × 111 |
| Prime factorization | 3 × 7 | 5 × 11 |
| Divisors count | 4 | 4 |
| Divisors | 1, 3, 7, 21 | 1, 5, 11, 55 |
| Number of properties | 1 | 1 |
| Semiprimes | 7th | 19th |
| Roman numberals | XXI | LV |
| Base 2 | 101012 | 1101112 |
| Base 3 | 2103 | 20013 |
| Base 4 | 1114 | 3134 |
| Base 5 | 415 | 2105 |
| Base 6 | 336 | 1316 |
| Base 7 | 307 | 1067 |
| Base 8 | 258 | 678 |
| Base 9 | 239 | 619 |
| Base 10 | 2110 | 5510 |
| Base 11 | 1a11 | 5011 |
| Base 12 | 1912 | 4712 |
| Base 13 | 1813 | 4313 |
| Base 14 | 1714 | 3d14 |
| Base 15 | 1615 | 3a15 |
| Base 16 | 1516 | 3716 |