Compare 3 vs 15
| Property | 3 | 15 |
|---|---|---|
| Type | prime | semiprime |
| Unique factors | 1 | 2 |
| Total factors | 1 | 2 |
| Prime factorization | 31 | 31 × 51 |
| Prime factorization | 3 | 3 × 5 |
| Divisors count | 2 | 4 |
| Divisors | 1, 3 | 1, 3, 5, 15 |
| Number of properties | 29 | 1 |
| Additive primes | 2nd | |
| Chen primes | 2nd | |
| Class 1+ primes | 2nd | |
| Cousin primes (1st member) | 1st | |
| Cullen primes | 1st | |
| Euclid primes | 2nd | |
| Factorial primes | 2nd | |
| Fermat primes | 1st | |
| Fibonacci primes | 2nd | |
| Left-truncatable primes | 2nd | |
| Leyland primes | 1st | |
| Lucas primes | 2nd | |
| Lucky primes | 1st | |
| Mersenne primes | 1st | |
| Multiplicative primes | 2nd | |
| Palindromic primes | 2nd | |
| Pierpont primes | 2nd | |
| Pierpont primes of the 2nd kind | 2nd | |
| Primes | 2nd | |
| Proth primes | 1st | |
| Right-truncatable primes | 2nd | |
| Semiprimes | 6th | |
| Solinas primes | 1st | |
| Sophie germain primes | 2nd | |
| Super primes | 1st | |
| Twin primes (1st member) | 1st | |
| Two-sided primes | 2nd | |
| Ulam primes | 2nd | |
| Wagstaff primes | 1st | |
| Wedderburn-etherington primes | 2nd | |
| Roman numberals | III | XV |
| Base 2 | 112 | 11112 |
| Base 3 | 103 | 1203 |
| Base 4 | 34 | 334 |
| Base 5 | 35 | 305 |
| Base 6 | 36 | 236 |
| Base 7 | 37 | 217 |
| Base 8 | 38 | 178 |
| Base 9 | 39 | 169 |
| Base 10 | 310 | 1510 |
| Base 11 | 311 | 1411 |
| Base 12 | 312 | 1312 |
| Base 13 | 313 | 1213 |
| Base 14 | 314 | 1114 |
| Base 15 | 315 | 1015 |
| Base 16 | 316 | f16 |