638168828 has 24 divisors (see below), whose sum is σ = 1219741824. Its totient is φ = 289738800.

The previous prime is 638168819. The next prime is 638168837. The reversal of 638168828 is 828861836.

It is an interprime number because it is at equal distance from previous prime (638168819) and next prime (638168837).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31913 + ... + 47903.

It is an arithmetic number, because the mean of its divisors is an integer number (50822576).

Almost surely, 2^638168828 is an apocalyptic number.

It is an amenable number.

638168828 is a deficient number, since it is larger than the sum of its proper divisors (581572996).

638168828 is a wasteful number, since it uses less digits than its factorization.

638168828 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16913 (or 16911 counting only the distinct ones).

The product of its digits is 884736, while the sum is 50.

The square root of 638168828 is about 25262.0036418333. The cubic root of 638168828 is about 860.9511866184.

The spelling of 638168828 in words is "six hundred thirty-eight million, one hundred sixty-eight thousand, eight hundred twenty-eight".