639529079 has 4 divisors (see below), whose sum is σ = 730890384. Its totient is φ = 548167776.

The previous prime is 639528971. The next prime is 639529081. The reversal of 639529079 is 970925936.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-639529079 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639529279) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45680642 + ... + 45680655.

It is an arithmetic number, because the mean of its divisors is an integer number (182722596).

Almost surely, 2^639529079 is an apocalyptic number.

639529079 is a deficient number, since it is larger than the sum of its proper divisors (91361305).

639529079 is an equidigital number, since it uses as much as digits as its factorization.

639529079 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91361304.

The product of its (nonzero) digits is 918540, while the sum is 50.

The square root of 639529079 is about 25288.9121751016. The cubic root of 639529079 is about 861.5624557034.

The spelling of 639529079 in words is "six hundred thirty-nine million, five hundred twenty-nine thousand, seventy-nine".