640264626 has 24 divisors (see below), whose sum is σ = 1389315564. Its totient is φ = 213102240.

The previous prime is 640264619. The next prime is 640264649. The reversal of 640264626 is 626462046.

640264626 is a `hidden beast` number, since 6 + 4 + 0 + 2 + 646 + 2 + 6 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 372451401 + 267813225 = 19299^2 + 16365^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 14085 + ... + 38456.

Almost surely, 2^640264626 is an apocalyptic number.

640264626 is an abundant number, since it is smaller than the sum of its proper divisors (749050938).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

640264626 is a wasteful number, since it uses less digits than its factorization.

640264626 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53226 (or 53223 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 36.

The square root of 640264626 is about 25303.4508713733. The cubic root of 640264626 is about 861.8926345284.

The spelling of 640264626 in words is "six hundred forty million, two hundred sixty-four thousand, six hundred twenty-six".