639834631 has 8 divisors (see below), whose sum is σ = 668726784. Its totient is φ = 611031960.

The previous prime is 639834607. The next prime is 639834647. The reversal of 639834631 is 136438936.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 639834631 - 2¹⁵ = 639801863 is a prime.

It is a super-2 number, since 2×639834631² = 818776710053812322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639834691) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7531 + ... + 36556.

It is an arithmetic number, because the mean of its divisors is an integer number (83590848).

Almost surely, 2^639834631 is an apocalyptic number.

639834631 is a deficient number, since it is larger than the sum of its proper divisors (28892153).

639834631 is a wasteful number, since it uses less digits than its factorization.

639834631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44741.

The product of its digits is 279936, while the sum is 43.

The square root of 639834631 is about 25294.9526783507. The cubic root of 639834631 is about 861.6996453043.

The spelling of 639834631 in words is "six hundred thirty-nine million, eight hundred thirty-four thousand, six hundred thirty-one".