639500128 has 24 divisors (see below), whose sum is σ = 1288298088. Its totient is φ = 312313344.

The previous prime is 639500123. The next prime is 639500131. The reversal of 639500128 is 821005936.

It is a junction number, because it is equal to n+sod(n) for n = 639500093 and 639500102.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639500123) 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 3 ways as a sum of consecutive naturals, for example, 231001 + ... + 233752.

It is an arithmetic number, because the mean of its divisors is an integer number (53679087).

Almost surely, 2^639500128 is an apocalyptic number.

It is an amenable number.

639500128 is an abundant number, since it is smaller than the sum of its proper divisors (648797960).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

639500128 is a wasteful number, since it uses less digits than its factorization.

639500128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 464806 (or 464798 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 34.

The square root of 639500128 is about 25288.3397636144. The cubic root of 639500128 is about 861.5494547459.

The spelling of 639500128 in words is "six hundred thirty-nine million, five hundred thousand, one hundred twenty-eight".