631884915721 has 4 divisors (see below), whose sum is σ = 638019720832. Its totient is φ = 625750110612.

The previous prime is 631884915631. The next prime is 631884915743. The reversal of 631884915721 is 127519488136.

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 631884915721 - 2¹⁹ = 631884391433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (631884945721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3067402401 + ... + 3067402606.

It is an arithmetic number, because the mean of its divisors is an integer number (159504930208).

Almost surely, 2^631884915721 is an apocalyptic number.

It is an amenable number.

631884915721 is a deficient number, since it is larger than the sum of its proper divisors (6134805111).

631884915721 is a wasteful number, since it uses less digits than its factorization.

631884915721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6134805110.

The product of its digits is 2903040, while the sum is 55.

The spelling of 631884915721 in words is "six hundred thirty-one billion, eight hundred eighty-four million, nine hundred fifteen thousand, seven hundred twenty-one".