638586566809 has 4 divisors (see below), whose sum is σ = 638591264640. Its totient is φ = 638581868980.

The previous prime is 638586566773. The next prime is 638586566887. The reversal of 638586566809 is 908665685836.

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 638586566809 - 2¹¹ = 638586564761 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638586563809) 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, 2138749 + ... + 2418970.

It is an arithmetic number, because the mean of its divisors is an integer number (159647816160).

Almost surely, 2^638586566809 is an apocalyptic number.

It is an amenable number.

638586566809 is a deficient number, since it is larger than the sum of its proper divisors (4697831).

638586566809 is a wasteful number, since it uses less digits than its factorization.

638586566809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4697830.

The product of its (nonzero) digits is 447897600, while the sum is 70.

The spelling of 638586566809 in words is "six hundred thirty-eight billion, five hundred eighty-six million, five hundred sixty-six thousand, eight hundred nine".