638428896 has 72 divisors (see below), whose sum is σ = 2074900464. Its totient is φ = 182407680.

The previous prime is 638428891. The next prime is 638428919. The reversal of 638428896 is 698824836.

It is a tau number, because it is divible by the number of its divisors (72).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638428891) 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 11 ways as a sum of consecutive naturals, for example, 156325 + ... + 160356.

It is an arithmetic number, because the mean of its divisors is an integer number (28818062).

Almost surely, 2^638428896 is an apocalyptic number.

It is an amenable number.

638428896 is an abundant number, since it is smaller than the sum of its proper divisors (1436471568).

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

638428896 is a wasteful number, since it uses less digits than its factorization.

638428896 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 316704 (or 316693 counting only the distinct ones).

The product of its digits is 3981312, while the sum is 54.

The square root of 638428896 is about 25267.1505318665. The cubic root of 638428896 is about 861.0681229915.

The spelling of 638428896 in words is "six hundred thirty-eight million, four hundred twenty-eight thousand, eight hundred ninety-six".