639407638 has 8 divisors (see below), whose sum is σ = 1015529832. Its totient is φ = 300897696.

The previous prime is 639407597. The next prime is 639407641. The reversal of 639407638 is 836704936.

It is a sphenic number, since it is the product of 3 distinct primes.

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 3 ways as a sum of consecutive naturals, for example, 9403020 + ... + 9403087.

It is an arithmetic number, because the mean of its divisors is an integer number (126941229).

Almost surely, 2^639407638 is an apocalyptic number.

639407638 is a deficient number, since it is larger than the sum of its proper divisors (376122194).

639407638 is a wasteful number, since it uses less digits than its factorization.

639407638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18806126.

The product of its (nonzero) digits is 653184, while the sum is 46.

The square root of 639407638 is about 25286.5109890629. The cubic root of 639407638 is about 861.5079178499.

The spelling of 639407638 in words is "six hundred thirty-nine million, four hundred seven thousand, six hundred thirty-eight".