639646936 has 8 divisors (see below), whose sum is σ = 1199338020. Its totient is φ = 319823464.

The previous prime is 639646927. The next prime is 639646937.

639646936 is nontrivially palindromic in base 10.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639646937) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39977926 + ... + 39977941.

Almost surely, 2^639646936 is an apocalyptic number.

It is an amenable number.

639646936 is a deficient number, since it is larger than the sum of its proper divisors (559691084).

639646936 is a wasteful number, since it uses less digits than its factorization.

639646936 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79955873 (or 79955869 counting only the distinct ones).

The product of its digits is 3779136, while the sum is 52.

The square root of 639646936 is about 25291.2422787019. The cubic root of 639646936 is about 861.6153774196.

The spelling of 639646936 in words is "six hundred thirty-nine million, six hundred forty-six thousand, nine hundred thirty-six".