645552290 has 16 divisors (see below), whose sum is σ = 1162290168. Its totient is φ = 258155136.

The previous prime is 645552269. The next prime is 645552301. The reversal of 645552290 is 92255546.

It can be written as a sum of positive squares in 4 ways, for example, as 281467729 + 364084561 = 16777^2 + 19081^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 59744 + ... + 69716.

Almost surely, 2^645552290 is an apocalyptic number.

645552290 is a deficient number, since it is larger than the sum of its proper divisors (516737878).

645552290 is a wasteful number, since it uses less digits than its factorization.

645552290 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16453.

The product of its (nonzero) digits is 108000, while the sum is 38.

The square root of 645552290 is about 25407.7210705722. The cubic root of 645552290 is about 864.2587968238.

The spelling of 645552290 in words is "six hundred forty-five million, five hundred fifty-two thousand, two hundred ninety".