639747936 has 96 divisors (see below), whose sum is σ = 1964188800. Its totient is φ = 202020480.

The previous prime is 639747919. The next prime is 639747943.

639747936 is nontrivially palindromic in base 10.

It is a tau number, because it is divible by the number of its divisors (96).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3070 + ... + 35901.

It is an arithmetic number, because the mean of its divisors is an integer number (20460300).

Almost surely, 2^639747936 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 639747936, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (982094400).

639747936 is an abundant number, since it is smaller than the sum of its proper divisors (1324440864).

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

639747936 is a wasteful number, since it uses less digits than its factorization.

639747936 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39009 (or 38995 counting only the distinct ones).

The product of its digits is 5143824, while the sum is 54.

The square root of 639747936 is about 25293.2389384990. The cubic root of 639747936 is about 861.6607246095.

The spelling of 639747936 in words is "six hundred thirty-nine million, seven hundred forty-seven thousand, nine hundred thirty-six".