56 = 23 x 7.
56 is the sum of the first six triangular numbers: 1 + 3 + .6 + 10 + 15 + 21 = 56. Hence, it is a tetrahedral number, the number of balls you can put in a triangular pyramid: 1, 4, 10, 20, 35, 56, 84, 120, . . .
56 is the sum of six consecutive prime numbers: 3 + 5 + 7 + 11 + 13 + 17 = 56.
56 men signed the Declaration of Independence in 1776, which led to the formation of the United States of America.
Source: Number Gossip