638985792173 has 4 divisors (see below), whose sum is σ = 672616623360. Its totient is φ = 605354960988.

The previous prime is 638985792139. The next prime is 638985792187. The reversal of 638985792173 is 371297589836.

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 638985792173 - 2¹⁰ = 638985791149 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 (638985792073) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16815415565 + ... + 16815415602.

It is an arithmetic number, because the mean of its divisors is an integer number (168154155840).

Almost surely, 2^638985792173 is an apocalyptic number.

It is an amenable number.

638985792173 is a deficient number, since it is larger than the sum of its proper divisors (33630831187).

638985792173 is a wasteful number, since it uses less digits than its factorization.

638985792173 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33630831186.

The product of its digits is 137168640, while the sum is 68.

The spelling of 638985792173 in words is "six hundred thirty-eight billion, nine hundred eighty-five million, seven hundred ninety-two thousand, one hundred seventy-three".