31975891 has 2 divisors, whose sum is σ = 31975892. Its totient is φ = 31975890.

The previous prime is 31975871. The next prime is 31975897. The reversal of 31975891 is 19857913.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 31975891 - 2⁹ = 31975379 is a prime.

It is not a weakly prime, because it can be changed into another prime (31975897) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15987945 + 15987946.

It is an arithmetic number, because the mean of its divisors is an integer number (15987946).

Almost surely, 2^31975891 is an apocalyptic number.

31975891 is a deficient number, since it is larger than the sum of its proper divisors (1).

31975891 is an equidigital number, since it uses as much as digits as its factorization.

31975891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 68040, while the sum is 43.

The square root of 31975891 is about 5654.7228932990. The cubic root of 31975891 is about 317.4004598372.

The spelling of 31975891 in words is "thirty-one million, nine hundred seventy-five thousand, eight hundred ninety-one".