315631891 has 2 divisors, whose sum is σ = 315631892. Its totient is φ = 315631890.

The previous prime is 315631847. The next prime is 315631913. The reversal of 315631891 is 198136513.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-315631891 is a prime.

It is a super-3 number, since 3×315631891³ (a number of 26 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 315631891.

It is not a weakly prime, because it can be changed into another prime (315631831) 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, 157815945 + 157815946.

It is an arithmetic number, because the mean of its divisors is an integer number (157815946).

Almost surely, 2^315631891 is an apocalyptic number.

315631891 is a deficient number, since it is larger than the sum of its proper divisors (1).

315631891 is an equidigital number, since it uses as much as digits as its factorization.

315631891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 19440, while the sum is 37.

The square root of 315631891 is about 17766.0319430085. The cubic root of 315631891 is about 680.8638753912.

The spelling of 315631891 in words is "three hundred fifteen million, six hundred thirty-one thousand, eight hundred ninety-one".