Compare 1921 vs 1931
| Property | 1921 | 1931 |
|---|---|---|
| Type | semiprime | prime |
| Unique factors | 2 | 1 |
| Total factors | 2 | 1 |
| Prime factorization | 171 × 1131 | 19311 |
| Prime factorization | 17 × 113 | 1931 |
| Divisors count | 4 | 2 |
| Divisors | 1, 17, 113, 1921 | 1, 1931 |
| Number of properties | 1 | 5 |
| Chen primes | 182nd | |
| Harmonic primes | 108th | |
| Primes | 294th | |
| Semiprimes | 552nd | |
| Sophie germain primes | 59th | |
| Twin primes (1st member) | 59th | |
| Roman numberals | MCMXXI | MCMXXXI |
| Base 2 | 111100000012 | 111100010112 |
| Base 3 | 21220113 | 21221123 |
| Base 4 | 1320014 | 1320234 |
| Base 5 | 301415 | 302115 |
| Base 6 | 125216 | 125356 |
| Base 7 | 54137 | 54267 |
| Base 8 | 36018 | 36138 |
| Base 9 | 25649 | 25759 |
| Base 10 | 192110 | 193110 |
| Base 11 | 149711 | 14a611 |
| Base 12 | 114112 | 114b12 |
| Base 13 | b4a13 | b5713 |
| Base 14 | 9b314 | 9bd14 |
| Base 15 | 88115 | 88b15 |
| Base 16 | 78116 | 78b16 |