638580738021 has 32 divisors (see below), whose sum is σ = 884013273600. Its totient is φ = 409543646400.

The previous prime is 638580737903. The next prime is 638580738049. The reversal of 638580738021 is 120837085836.

638580738021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 638580738021 - 2¹¹ = 638580735973 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638580738121) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 34645410 + ... + 34663836.

It is an arithmetic number, because the mean of its divisors is an integer number (27625414800).

Almost surely, 2^638580738021 is an apocalyptic number.

It is an amenable number.

638580738021 is a deficient number, since it is larger than the sum of its proper divisors (245432535579).

638580738021 is a wasteful number, since it uses less digits than its factorization.

638580738021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19889.

The product of its (nonzero) digits is 1935360, while the sum is 51.

The spelling of 638580738021 in words is "six hundred thirty-eight billion, five hundred eighty million, seven hundred thirty-eight thousand, twenty-one".