50 = 2 x 52.
50 = 8 + 9 + 10 + 11 + 12.
50 can be expressed as a sum of primes in two distinct ways such that all primes involved are consecutive: 50 = 2 + 5 + 7 + 17 + 19 = 3 + 11 + 13 + 23.
50 is the smallest number with two representations as a sum of two squares: 50 = 12 + 72 = 52 + 52.
50 is 1212 in base 3, 101 in base 7, and 55 in base 9.
The flag of the United States of America has 50 stars representing its 50 constituent states. If you count stars along the diagonals, you get the sum 1 + 3 + 5 + 7 + 9 + 9 + 7 + 5 + 3 + 1 = 50.
Source: Number Gossip
