639911706 has 32 divisors (see below), whose sum is σ = 1465271808. Its totient is φ = 182504880.

The previous prime is 639911689. The next prime is 639911717. The reversal of 639911706 is 607119936.

It is a Harshad number since it is a multiple of its sum of digits (42).

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, 10641 + ... + 37323.

It is an arithmetic number, because the mean of its divisors is an integer number (45789744).

Almost surely, 2^639911706 is an apocalyptic number.

639911706 is an abundant number, since it is smaller than the sum of its proper divisors (825360102).

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

639911706 is a wasteful number, since it uses less digits than its factorization.

639911706 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27266.

The product of its (nonzero) digits is 61236, while the sum is 42.

The square root of 639911706 is about 25296.4761577576. The cubic root of 639911706 is about 861.7342442617.

The spelling of 639911706 in words is "six hundred thirty-nine million, nine hundred eleven thousand, seven hundred six".