639750685 has 16 divisors (see below), whose sum is σ = 878846976. Its totient is φ = 437948928.

The previous prime is 639750679. The next prime is 639750719. The reversal of 639750685 is 586057936.

It is a cyclic number.

It is not a de Polignac number, because 639750685 - 2¹⁵ = 639717917 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6189 + ... + 36301.

It is an arithmetic number, because the mean of its divisors is an integer number (54927936).

Almost surely, 2^639750685 is an apocalyptic number.

It is an amenable number.

639750685 is a deficient number, since it is larger than the sum of its proper divisors (239096291).

639750685 is a wasteful number, since it uses less digits than its factorization.

639750685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30732.

The product of its (nonzero) digits is 1360800, while the sum is 49.

The square root of 639750685 is about 25293.2932810261. The cubic root of 639750685 is about 861.6619587945.

The spelling of 639750685 in words is "six hundred thirty-nine million, seven hundred fifty thousand, six hundred eighty-five".