31108391 has 2 divisors, whose sum is σ = 31108392. Its totient is φ = 31108390.

The previous prime is 31108367. The next prime is 31108411. The reversal of 31108391 is 19380113.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 31108391 - 2⁶ = 31108327 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31108391.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31108331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15554195 + 15554196.

It is an arithmetic number, because the mean of its divisors is an integer number (15554196).

Almost surely, 2^31108391 is an apocalyptic number.

31108391 is a deficient number, since it is larger than the sum of its proper divisors (1).

31108391 is an equidigital number, since it uses as much as digits as its factorization.

31108391 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 648, while the sum is 26.

The square root of 31108391 is about 5577.4896683006. The cubic root of 31108391 is about 314.5037655741.

The spelling of 31108391 in words is "thirty-one million, one hundred eight thousand, three hundred ninety-one".