Compare 1618 vs 1621
| Property | 1618 | 1621 |
|---|---|---|
| Type | semiprime | prime |
| Unique factors | 2 | 1 |
| Total factors | 2 | 1 |
| Prime factorization | 21 × 8091 | 16211 |
| Prime factorization | 2 × 809 | 1621 |
| Divisors count | 4 | 2 |
| Divisors | 1, 2, 809, 1618 | 1, 1621 |
| Number of properties | 1 | 8 |
| Chen primes | 163rd | |
| Harmonic primes | 89th | |
| Long primes | 101st | |
| Primes | 257th | |
| Pythagorean primes | 123rd | |
| Semiprimes | 464th | |
| Sexy primes (1st member) | 111th | |
| Super primes | 55th | |
| Twin primes (2nd member) | 52nd | |
| Roman numberals | MDCXVIII | MDCXXI |
| Base 2 | 110010100102 | 110010101012 |
| Base 3 | 20122213 | 20200013 |
| Base 4 | 1211024 | 1211114 |
| Base 5 | 224335 | 224415 |
| Base 6 | 112546 | 113016 |
| Base 7 | 45017 | 45047 |
| Base 8 | 31228 | 31258 |
| Base 9 | 21879 | 22019 |
| Base 10 | 161810 | 162110 |
| Base 11 | 124111 | 124411 |
| Base 12 | b2a12 | b3112 |
| Base 13 | 97613 | 97913 |
| Base 14 | 83814 | 83b14 |
| Base 15 | 72d15 | 73115 |
| Base 16 | 65216 | 65516 |