631631659721 has 8 divisors (see below), whose sum is σ = 674922120840. Its totient is φ = 589022938368.

The previous prime is 631631659667. The next prime is 631631659739. The reversal of 631631659721 is 127956136136.

It can be written as a sum of positive squares in 4 ways, for example, as 276402547600 + 355229112121 = 525740^2 + 596011^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 631631659721 - 2⁶ = 631631659657 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 631631659721.

It is not an unprimeable number, because it can be changed into a prime (631631689721) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 170433026 + ... + 170436731.

It is an arithmetic number, because the mean of its divisors is an integer number (84365265105).

Almost surely, 2^631631659721 is an apocalyptic number.

It is an amenable number.

631631659721 is a deficient number, since it is larger than the sum of its proper divisors (43290461119).

631631659721 is a wasteful number, since it uses less digits than its factorization.

631631659721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 340869883.

The product of its digits is 1224720, while the sum is 50.

The spelling of 631631659721 in words is "six hundred thirty-one billion, six hundred thirty-one million, six hundred fifty-nine thousand, seven hundred twenty-one".