631688257 has 4 divisors (see below), whose sum is σ = 631761840. Its totient is φ = 631614676.

The previous prime is 631688249. The next prime is 631688273. The reversal of 631688257 is 752886136.

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 631688257 - 2³ = 631688249 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (631688657) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21907 + ... + 41752.

It is an arithmetic number, because the mean of its divisors is an integer number (157940460).

Almost surely, 2^631688257 is an apocalyptic number.

It is an amenable number.

631688257 is a deficient number, since it is larger than the sum of its proper divisors (73583).

631688257 is an equidigital number, since it uses as much as digits as its factorization.

631688257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73582.

The product of its digits is 483840, while the sum is 46.

The square root of 631688257 is about 25133.4091798148. The cubic root of 631688257 is about 858.0269609892.

The spelling of 631688257 in words is "six hundred thirty-one million, six hundred eighty-eight thousand, two hundred fifty-seven".