639545078 has 4 divisors (see below), whose sum is σ = 959317620. Its totient is φ = 319772538.

The previous prime is 639545059. The next prime is 639545087. The reversal of 639545078 is 870545936.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 159886268 + ... + 159886271.

It is an arithmetic number, because the mean of its divisors is an integer number (239829405).

Almost surely, 2^639545078 is an apocalyptic number.

639545078 is a deficient number, since it is larger than the sum of its proper divisors (319772542).

639545078 is a wasteful number, since it uses less digits than its factorization.

639545078 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 319772541.

The product of its (nonzero) digits is 907200, while the sum is 47.

The square root of 639545078 is about 25289.2284975244. The cubic root of 639545078 is about 861.5696401683.

The spelling of 639545078 in words is "six hundred thirty-nine million, five hundred forty-five thousand, seventy-eight".