638342720 has 56 divisors (see below), whose sum is σ = 1552431744. Its totient is φ = 249898496.

The previous prime is 638342699. The next prime is 638342723. The reversal of 638342720 is 27243836.

It is a hoax number, since the sum of its digits (35) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (638342723) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6182 + ... + 36261.

Almost surely, 2^638342720 is an apocalyptic number.

It is an amenable number.

638342720 is an abundant number, since it is smaller than the sum of its proper divisors (914089024).

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

638342720 is a wasteful number, since it uses less digits than its factorization.

638342720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42507 (or 42497 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 35.

The square root of 638342720 is about 25265.4451771585. The cubic root of 638342720 is about 861.0293785331.

The spelling of 638342720 in words is "six hundred thirty-eight million, three hundred forty-two thousand, seven hundred twenty".