638724360877 has 4 divisors (see below), whose sum is σ = 638750174976. Its totient is φ = 638698546780.

The previous prime is 638724360853. The next prime is 638724360919. The reversal of 638724360877 is 778063427836.

638724360877 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 638724360877 - 2²³ = 638715972269 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638724360847) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12869899 + ... + 12919432.

It is an arithmetic number, because the mean of its divisors is an integer number (159687543744).

Almost surely, 2^638724360877 is an apocalyptic number.

It is an amenable number.

638724360877 is a deficient number, since it is larger than the sum of its proper divisors (25814099).

638724360877 is a wasteful number, since it uses less digits than its factorization.

638724360877 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25814098.

The product of its (nonzero) digits is 56899584, while the sum is 61.

The spelling of 638724360877 in words is "six hundred thirty-eight billion, seven hundred twenty-four million, three hundred sixty thousand, eight hundred seventy-seven".