639438252 has 12 divisors (see below), whose sum is σ = 1492022616. Its totient is φ = 213146080.

The previous prime is 639438229. The next prime is 639438257. The reversal of 639438252 is 252834936.

It is a tau number, because it is divible by the number of its divisors (12).

It is not an unprimeable number, because it can be changed into a prime (639438257) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26643249 + ... + 26643272.

It is an arithmetic number, because the mean of its divisors is an integer number (124335218).

Almost surely, 2^639438252 is an apocalyptic number.

It is an amenable number.

639438252 is an abundant number, since it is smaller than the sum of its proper divisors (852584364).

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

639438252 is a wasteful number, since it uses less digits than its factorization.

639438252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53286528 (or 53286526 counting only the distinct ones).

The product of its digits is 311040, while the sum is 42.

The square root of 639438252 is about 25287.1163243261. The cubic root of 639438252 is about 861.5216669206.

The spelling of 639438252 in words is "six hundred thirty-nine million, four hundred thirty-eight thousand, two hundred fifty-two".