639623705 has 24 divisors (see below), whose sum is σ = 911875968. Its totient is φ = 429259488.

The previous prime is 639623701. The next prime is 639623707. The reversal of 639623705 is 507326936.

639623705 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 639623705 - 2² = 639623701 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (639623701) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 16259 + ... + 39288.

It is an arithmetic number, because the mean of its divisors is an integer number (37994832).

Almost surely, 2^639623705 is an apocalyptic number.

It is an amenable number.

639623705 is a deficient number, since it is larger than the sum of its proper divisors (272252263).

639623705 is a wasteful number, since it uses less digits than its factorization.

639623705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55613 (or 55606 counting only the distinct ones).

The product of its (nonzero) digits is 204120, while the sum is 41.

The square root of 639623705 is about 25290.7830048814. The cubic root of 639623705 is about 861.6049464417.

The spelling of 639623705 in words is "six hundred thirty-nine million, six hundred twenty-three thousand, seven hundred five".