638580885637 has 4 divisors (see below), whose sum is σ = 638607705696. Its totient is φ = 638554065580.

The previous prime is 638580885629. The next prime is 638580885661. The reversal of 638580885637 is 736588085836.

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 638580885637 - 2³ = 638580885629 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 (638580888637) 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, 13374283 + ... + 13421944.

It is an arithmetic number, because the mean of its divisors is an integer number (159651926424).

Almost surely, 2^638580885637 is an apocalyptic number.

It is an amenable number.

638580885637 is a deficient number, since it is larger than the sum of its proper divisors (26820059).

638580885637 is a wasteful number, since it uses less digits than its factorization.

638580885637 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26820058.

The product of its (nonzero) digits is 232243200, while the sum is 67.

The spelling of 638580885637 in words is "six hundred thirty-eight billion, five hundred eighty million, eight hundred eighty-five thousand, six hundred thirty-seven".