The folowing table expresses '665' in various number bases. 'DRx' shows the result of 'digit reducing' resulting in an X-digit long number.
| Base | DR10 | DR9 | DR8 | DR7 | DR6 | DR5 | DR4 | DR3 | DR2 | DR1 |
|---|---|---|---|---|---|---|---|---|---|---|
| 2 | 1010011001 | 101 | 10 | 1 | ||||||
| 3 | 220122 | 100 | 1 | |||||||
| 4 | 22121 | 20 | 2 | |||||||
| 5 | 10130 | 10 | 1 | |||||||
| 6 | 3025 | 14 | 5 | |||||||
| 7 | 1640 | 14 | 5 | |||||||
| 8 | 1231 | 7 | ||||||||
| 9 | 818 | 18,10 | 1 | |||||||
| 10 | 665 | 17 | 8 | |||||||
| 11 | 555 | 14 | 5 | |||||||
| 12 | 475 | 14 | 5 | |||||||
| 13 | 3C2 | 14 | 5 | |||||||
| 14 | 357 | 11 | 2 | |||||||
| 15 | 2E5 | 16 | 7 | |||||||
| 16 | 299 | 14 | 5 |
Factors: 5 * 7 * 19
665 is in the Pythagorean Triple: (432, 665, 793).