639884173321 has 4 divisors (see below), whose sum is σ = 641404088644. Its totient is φ = 638364258000.

The previous prime is 639884173307. The next prime is 639884173351. The reversal of 639884173321 is 123371488936.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 164251878400 + 475632294921 = 405280^2 + 689661^2 .

It is a cyclic number.

It is not a de Polignac number, because 639884173321 - 2⁷ = 639884173193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (639884173301) 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, 759957030 + ... + 759957871.

It is an arithmetic number, because the mean of its divisors is an integer number (160351022161).

Almost surely, 2^639884173321 is an apocalyptic number.

It is an amenable number.

639884173321 is a deficient number, since it is larger than the sum of its proper divisors (1519915323).

639884173321 is a wasteful number, since it uses less digits than its factorization.

639884173321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1519915322.

The product of its digits is 5225472, while the sum is 55.

The spelling of 639884173321 in words is "six hundred thirty-nine billion, eight hundred eighty-four million, one hundred seventy-three thousand, three hundred twenty-one".