The folowing table expresses '15' in various number bases. 'DRx' shows the result of 'digit reducing' resulting in an X-digit long number.
Base | DR4 | DR3 | DR2 | DR1 |
---|---|---|---|---|
2 | 1111 | 100 | 1 | |
3 | 120 | 10 | 1 | |
4 | 33,12 | 3 | ||
5 | 30 | 3 | ||
6 | 23 | 5 | ||
7 | 21 | 3 | ||
8 | 17,10 | 1 | ||
9 | 16 | 7 | ||
10 | 15 | 6 | ||
11 | 14 | 5 | ||
12 | 13 | 4 | ||
13 | 12 | 3 | ||
14 | 11 | 2 | ||
15 | 10 | 1 | ||
16 | F |
Factors: 3 * 5
15 is in the Pythagorean Triples: (8, 15, 17), (15, 112, 113).
15 is the sum of the counting numbers from 1 to 5 (See 'The Sum/Product of the First N Counting Numbers').
A 'Pentadecagon' is a 'regular polygon' with 15 sides.
15 is the atomic weight of Phosphorus (P).