Compare 1981 vs 2021
| Property | 1981 | 2021 |
|---|---|---|
| Type | semiprime | semiprime |
| Unique factors | 2 | 2 |
| Total factors | 2 | 2 |
| Prime factorization | 71 × 2831 | 431 × 471 |
| Prime factorization | 7 × 283 | 43 × 47 |
| Divisors count | 4 | 4 |
| Divisors | 1, 7, 283, 1981 | 1, 43, 47, 2021 |
| Number of properties | 1 | 1 |
| Semiprimes | 572nd | 581st |
| Roman numberals | MCMLXXXI | MMXXI |
| Base 2 | 111101111012 | 111111001012 |
| Base 3 | 22011013 | 22022123 |
| Base 4 | 1323314 | 1332114 |
| Base 5 | 304115 | 310415 |
| Base 6 | 131016 | 132056 |
| Base 7 | 55307 | 56157 |
| Base 8 | 36758 | 37458 |
| Base 9 | 26419 | 26859 |
| Base 10 | 198110 | 202110 |
| Base 11 | 154111 | 157811 |
| Base 12 | 119112 | 120512 |
| Base 13 | b9513 | bc613 |
| Base 14 | a1714 | a4514 |
| Base 15 | 8c115 | 8eb15 |
| Base 16 | 7bd16 | 7e516 |