639909936 has 160 divisors (see below), whose sum is σ = 1925591040. Its totient is φ = 203212800.

The previous prime is 639909917. The next prime is 639909943.

639909936 is nontrivially palindromic in base 10.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 950496 + ... + 951168.

It is an arithmetic number, because the mean of its divisors is an integer number (12034944).

Almost surely, 2^639909936 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 639909936, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (962795520).

639909936 is an abundant number, since it is smaller than the sum of its proper divisors (1285681104).

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

639909936 is a wasteful number, since it uses less digits than its factorization.

639909936 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 792 (or 780 counting only the distinct ones).

The product of its (nonzero) digits is 2125764, while the sum is 54.

The square root of 639909936 is about 25296.4411726235. The cubic root of 639909936 is about 861.7334497401.

It can be divided in two parts, 639 and 909936, that added together give a triangular number (910575 = T₁₃₄₉).

The spelling of 639909936 in words is "six hundred thirty-nine million, nine hundred nine thousand, nine hundred thirty-six".