Compare 1981 vs 2005
| Property | 1981 | 2005 |
|---|---|---|
| Type | semiprime | semiprime |
| Unique factors | 2 | 2 |
| Total factors | 2 | 2 |
| Prime factorization | 71 × 2831 | 51 × 4011 |
| Prime factorization | 7 × 283 | 5 × 401 |
| Divisors count | 4 | 4 |
| Divisors | 1, 7, 283, 1981 | 1, 5, 401, 2005 |
| Number of properties | 1 | 1 |
| Semiprimes | 572nd | 578th |
| Roman numberals | MCMLXXXI | MMV |
| Base 2 | 111101111012 | 111110101012 |
| Base 3 | 22011013 | 22020213 |
| Base 4 | 1323314 | 1331114 |
| Base 5 | 304115 | 310105 |
| Base 6 | 131016 | 131416 |
| Base 7 | 55307 | 55637 |
| Base 8 | 36758 | 37258 |
| Base 9 | 26419 | 26679 |
| Base 10 | 198110 | 200510 |
| Base 11 | 154111 | 156311 |
| Base 12 | 119112 | 11b112 |
| Base 13 | b9513 | bb313 |
| Base 14 | a1714 | a3314 |
| Base 15 | 8c115 | 8da15 |
| Base 16 | 7bd16 | 7d516 |