145 is the natural number following 144 and preceding 146.

Although composite, 145 is a pseudoprime.

Given 145, the Mertens function returns 0.

145 is a pentagonal number and a centered square number.

145 = 1! + 4! + 5!. The only other numbers that have the property that they are the sum of the factorials of their digits are 1, 2 and 40585.

145 = 12² + 1² = 8² + 9². 145 is the fourth number that is the sum of two different pairs of squares.

For the year 145 AD, see 145.