Numeric Value: 28

The folowing table expresses '28' in various number bases. 'DRx' shows the result of 'digit reducing' resulting in an X-digit long number.

BaseDR5DR4DR3DR2DR1
211100  11,101
3 1001  2
4  130101
5  103 4
6   44,123
7   404
8   347
9   314
10   28,101
11   268
12   246
13   224
14   202
15   1DE
16   1CD

Math World

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.

Physical World

28 is the atomic weight of Nickel (Ni).