145 (one hundred [and] forty-five) is the natural number following 144 and preceding 146.
In mathematics Although composite, 145 is a Fermat pseudoprime in sixteen bases with b < 145. In four of those bases, it is a strong pseudoprime: 1, 12, 17, and 144. The Mertens function returns 0. 145 is a pentagonal number and a centered square number. . 145 is the fourth number that is the sum of two different pairs of squares. Also, 145 is the result of 34 + 43, making it a Leyland number. , making it a factorion. The only other numbers that have this property are 1, 2 and 40585. , making 145 the smallest number that can be written as the sum of a square number and a factorial in 3 ways. The next number with this property is 46249.
References Wells, D. The Penguin Dictionary of Curious and Interesting Numbers London: Penguin Group. (1987): 140
External links
The Natural Number 145