Compare 15 vs 18
| Property | 15 | 18 |
|---|---|---|
| Type | semiprime | composite number |
| Unique factors | 2 | 2 |
| Total factors | 2 | 3 |
| Prime factorization | 31 × 51 | 21 × 32 |
| Prime factorization | 3 × 5 | 2 × 3 × 3 |
| Divisors count | 4 | 6 |
| Divisors | 1, 3, 5, 15 | 1, 2, 3, 6, 9, 18 |
| Number of properties | 1 | 0 |
| Semiprimes | 6th | |
| Roman numberals | XV | XVIII |
| Base 2 | 11112 | 100102 |
| Base 3 | 1203 | 2003 |
| Base 4 | 334 | 1024 |
| Base 5 | 305 | 335 |
| Base 6 | 236 | 306 |
| Base 7 | 217 | 247 |
| Base 8 | 178 | 228 |
| Base 9 | 169 | 209 |
| Base 10 | 1510 | 1810 |
| Base 11 | 1411 | 1711 |
| Base 12 | 1312 | 1612 |
| Base 13 | 1213 | 1513 |
| Base 14 | 1114 | 1414 |
| Base 15 | 1015 | 1315 |
| Base 16 | f16 | 1216 |