325

325 = 5² x 13.

325 is the 25th triangular number (the sum of the first 25 integers): 1 + 2 + 3 + . . . + 25 = 325.

325 is a hexagonal number.

In base 2, 325 is the palindromic number 101000101; in base 4, it is 11011; and in base 8, it is 505.

325 is the smallest number to be the sum of two squares in three different ways: 325 = 1² + 18² = 6² + 17² = 10² + 15².

325 is the hypotenuse of two primitive Pythagorean triples: 325² = 36² + 323² = 204² + 253².

Currently undergoing restoration, the USS LST-325, launched in 1942, participated in the invasion of Sicily in 1943 and in June 1944 landed at Omaha Beach.

Source: Positive Integers