631318321 has 2 divisors, whose sum is σ = 631318322. Its totient is φ = 631318320.

The previous prime is 631318249. The next prime is 631318357. The reversal of 631318321 is 123813136.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 553190400 + 78127921 = 23520^2 + 8839^2 .

It is a cyclic number.

It is not a de Polignac number, because 631318321 - 2⁹ = 631317809 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 631318321.

It is not a weakly prime, because it can be changed into another prime (631318921) 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 as a sum of consecutive naturals, namely, 315659160 + 315659161.

It is an arithmetic number, because the mean of its divisors is an integer number (315659161).

Almost surely, 2^631318321 is an apocalyptic number.

It is an amenable number.

631318321 is a deficient number, since it is larger than the sum of its proper divisors (1).

631318321 is an equidigital number, since it uses as much as digits as its factorization.

631318321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2592, while the sum is 28.

The square root of 631318321 is about 25126.0486547328. The cubic root of 631318321 is about 857.8594326548.

The spelling of 631318321 in words is "six hundred thirty-one million, three hundred eighteen thousand, three hundred twenty-one".