640672672 has 12 divisors (see below), whose sum is σ = 1261324386. Its totient is φ = 320336320.

The previous prime is 640672667. The next prime is 640672673. The reversal of 640672672 is 276276046.

It is a happy number.

640672672 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 496576656 + 144096016 = 22284^2 + 12004^2 .

It is a super-2 number, since 2×640672672² = 820922945295239168, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (640672673) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10010479 + ... + 10010542.

Almost surely, 2^640672672 is an apocalyptic number.

It is an amenable number.

640672672 is a deficient number, since it is larger than the sum of its proper divisors (620651714).

640672672 is a wasteful number, since it uses less digits than its factorization.

640672672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20021031 (or 20021023 counting only the distinct ones).

The product of its (nonzero) digits is 169344, while the sum is 40.

The square root of 640672672 is about 25311.5126375331. The cubic root of 640672672 is about 862.0756927734.

The spelling of 640672672 in words is "six hundred forty million, six hundred seventy-two thousand, six hundred seventy-two".