639813658 has 16 divisors (see below), whose sum is σ = 1047357216. Its totient is φ = 290716240.

The previous prime is 639813617. The next prime is 639813659. The reversal of 639813658 is 856318936.

It is not an unprimeable number, because it can be changed into a prime (639813659) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 107160 + ... + 112972.

It is an arithmetic number, because the mean of its divisors is an integer number (65459826).

Almost surely, 2^639813658 is an apocalyptic number.

639813658 is a deficient number, since it is larger than the sum of its proper divisors (407543558).

639813658 is a wasteful number, since it uses less digits than its factorization.

639813658 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10829.

The product of its digits is 933120, while the sum is 49.

The square root of 639813658 is about 25294.5381060813. The cubic root of 639813658 is about 861.6902300464.

The spelling of 639813658 in words is "six hundred thirty-nine million, eight hundred thirteen thousand, six hundred fifty-eight".