631291 has 2 divisors, whose sum is σ = 631292. Its totient is φ = 631290.

The previous prime is 631273. The next prime is 631307. The reversal of 631291 is 192136.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 631291 - 2⁵ = 631259 is a prime.

It is not a weakly prime, because it can be changed into another prime (631271) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 315645 + 315646.

It is an arithmetic number, because the mean of its divisors is an integer number (315646).

2⁶³¹²⁹¹ is an apocalyptic number.

631291 is a deficient number, since it is larger than the sum of its proper divisors (1).

631291 is an equidigital number, since it uses as much as digits as its factorization.

631291 is an evil number, because the sum of its binary digits is even.

The product of its digits is 324, while the sum is 22.

The square root of 631291 is about 794.5382306724. The cubic root of 631291 is about 85.7847057537.

The spelling of 631291 in words is "six hundred thirty-one thousand, two hundred ninety-one".