631582759921 has 4 divisors (see below), whose sum is σ = 631666565092. Its totient is φ = 631498954752.

The previous prime is 631582759849. The next prime is 631582759981. The reversal of 631582759921 is 129957285136.

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 178896007521 + 452686752400 = 422961^2 + 672820^2 .

It is a cyclic number.

It is not a de Polignac number, because 631582759921 - 2³⁷ = 494143806449 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (631582759981) 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, 41891280 + ... + 41906353.

It is an arithmetic number, because the mean of its divisors is an integer number (157916641273).

Almost surely, 2^631582759921 is an apocalyptic number.

It is an amenable number.

631582759921 is a deficient number, since it is larger than the sum of its proper divisors (83805171).

631582759921 is an equidigital number, since it uses as much as digits as its factorization.

631582759921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83805170.

The product of its digits is 8164800, while the sum is 58.

The spelling of 631582759921 in words is "six hundred thirty-one billion, five hundred eighty-two million, seven hundred fifty-nine thousand, nine hundred twenty-one".