639874064 has 10 divisors (see below), whose sum is σ = 1239756030. Its totient is φ = 319937024.

The previous prime is 639874063. The next prime is 639874117. The reversal of 639874064 is 460478936.

It can be written as a sum of positive squares in only one way, i.e., 639078400 + 795664 = 25280^2 + 892^2 .

It is not an unprimeable number, because it can be changed into a prime (639874063) 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 as a sum of consecutive naturals, namely, 19996049 + ... + 19996080.

It is an arithmetic number, because the mean of its divisors is an integer number (123975603).

Almost surely, 2^639874064 is an apocalyptic number.

It is an amenable number.

639874064 is a deficient number, since it is larger than the sum of its proper divisors (599881966).

639874064 is a wasteful number, since it uses less digits than its factorization.

639874064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39992137 (or 39992131 counting only the distinct ones).

The product of its (nonzero) digits is 870912, while the sum is 47.

The square root of 639874064 is about 25295.7321301440. The cubic root of 639874064 is about 861.7173471199.

The spelling of 639874064 in words is "six hundred thirty-nine million, eight hundred seventy-four thousand, sixty-four".