639605085 has 24 divisors (see below), whose sum is σ = 1190450016. Its totient is φ = 292390560.

The previous prime is 639605053. The next prime is 639605089. The reversal of 639605085 is 580506936.

It is not a de Polignac number, because 639605085 - 2⁵ = 639605053 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639605089) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 434371 + ... + 435840.

It is an arithmetic number, because the mean of its divisors is an integer number (49602084).

Almost surely, 2^639605085 is an apocalyptic number.

It is an amenable number.

639605085 is a deficient number, since it is larger than the sum of its proper divisors (550844931).

639605085 is a wasteful number, since it uses less digits than its factorization.

639605085 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 870233 (or 870226 counting only the distinct ones).

The product of its (nonzero) digits is 194400, while the sum is 42.

The square root of 639605085 is about 25290.4148839041. The cubic root of 639605085 is about 861.5965856719.

The spelling of 639605085 in words is "six hundred thirty-nine million, six hundred five thousand, eighty-five".