31190891 has 2 divisors, whose sum is σ = 31190892. Its totient is φ = 31190890.

The previous prime is 31190879. The next prime is 31190899. The reversal of 31190891 is 19809113.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 31190891 - 2⁶ = 31190827 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (31190899) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15595445 + 15595446.

It is an arithmetic number, because the mean of its divisors is an integer number (15595446).

Almost surely, 2^31190891 is an apocalyptic number.

31190891 is a deficient number, since it is larger than the sum of its proper divisors (1).

31190891 is an equidigital number, since it uses as much as digits as its factorization.

31190891 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1944, while the sum is 32.

The square root of 31190891 is about 5584.8805716864. The cubic root of 31190891 is about 314.7815433338.

The spelling of 31190891 in words is "thirty-one million, one hundred ninety thousand, eight hundred ninety-one".