638814668 has 12 divisors (see below), whose sum is σ = 1156475040. Its totient is φ = 308393232.

The previous prime is 638814667. The next prime is 638814707. The reversal of 638814668 is 866418836.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (638814667) by changing a digit.

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, 2753396 + ... + 2753627.

It is an arithmetic number, because the mean of its divisors is an integer number (96372920).

Almost surely, 2^638814668 is an apocalyptic number.

It is an amenable number.

638814668 is a deficient number, since it is larger than the sum of its proper divisors (517660372).

638814668 is a wasteful number, since it uses less digits than its factorization.

638814668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5507056 (or 5507054 counting only the distinct ones).

The product of its digits is 1327104, while the sum is 50.

The square root of 638814668 is about 25274.7832433831. The cubic root of 638814668 is about 861.2415221440.

The spelling of 638814668 in words is "six hundred thirty-eight million, eight hundred fourteen thousand, six hundred sixty-eight".