639272840 has 16 divisors (see below), whose sum is σ = 1438363980. Its totient is φ = 255709120.

The previous prime is 639272831. The next prime is 639272857. The reversal of 639272840 is 48272936.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 531486916 + 107785924 = 23054^2 + 10382^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7990871 + ... + 7990950.

Almost surely, 2^639272840 is an apocalyptic number.

It is an amenable number.

639272840 is an abundant number, since it is smaller than the sum of its proper divisors (799091140).

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

639272840 is a wasteful number, since it uses less digits than its factorization.

639272840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15981832 (or 15981828 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 41.

The square root of 639272840 is about 25283.8454353763. The cubic root of 639272840 is about 861.4473734235.

The spelling of 639272840 in words is "six hundred thirty-nine million, two hundred seventy-two thousand, eight hundred forty".