The folowing table expresses '28' in various number bases. 'DRx' shows the result of 'digit reducing' resulting in an X-digit long number.
Base | DR5 | DR4 | DR3 | DR2 | DR1 |
---|---|---|---|---|---|
2 | 11100 | 11,10 | 1 | ||
3 | 1001 | 2 | |||
4 | 130 | 10 | 1 | ||
5 | 103 | 4 | |||
6 | 44,12 | 3 | |||
7 | 40 | 4 | |||
8 | 34 | 7 | |||
9 | 31 | 4 | |||
10 | 28,10 | 1 | |||
11 | 26 | 8 | |||
12 | 24 | 6 | |||
13 | 22 | 4 | |||
14 | 20 | 2 | |||
15 | 1D | E | |||
16 | 1C | D |
Factors: 22 * 7
28 is in the Pythagorean Triples: (28, 195, 197), (28, 45, 53).
28 is the sum of the counting numbers from 1 to 7 (See 'The Sum/Product of the First N Counting Numbers').
28 is the 2nd Perfect Number.
28 is the atomic weight of Nickel (Ni).