631968257 has 2 divisors, whose sum is σ = 631968258. Its totient is φ = 631968256.

The previous prime is 631968241. The next prime is 631968269. The reversal of 631968257 is 752869136.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 367450561 + 264517696 = 19169^2 + 16264^2 .

It is a cyclic number.

It is not a de Polignac number, because 631968257 - 2⁴ = 631968241 is a prime.

It is not a weakly prime, because it can be changed into another prime (631968277) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 315984128 + 315984129.

It is an arithmetic number, because the mean of its divisors is an integer number (315984129).

Almost surely, 2^631968257 is an apocalyptic number.

It is an amenable number.

631968257 is a deficient number, since it is larger than the sum of its proper divisors (1).

631968257 is an equidigital number, since it uses as much as digits as its factorization.

631968257 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 544320, while the sum is 47.

The square root of 631968257 is about 25138.9788376537. The cubic root of 631968257 is about 858.1537176386.

The spelling of 631968257 in words is "six hundred thirty-one million, nine hundred sixty-eight thousand, two hundred fifty-seven".