31311689 has 2 divisors, whose sum is σ = 31311690. Its totient is φ = 31311688.

The previous prime is 31311661. The next prime is 31311701. The reversal of 31311689 is 98611313.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18207289 + 13104400 = 4267^2 + 3620^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31311689 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (31311649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15655844 + 15655845.

It is an arithmetic number, because the mean of its divisors is an integer number (15655845).

Almost surely, 2^31311689 is an apocalyptic number.

It is an amenable number.

31311689 is a deficient number, since it is larger than the sum of its proper divisors (1).

31311689 is an equidigital number, since it uses as much as digits as its factorization.

31311689 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3888, while the sum is 32.

The square root of 31311689 is about 5595.6848553149. The cubic root of 31311689 is about 315.1873882937.

The spelling of 31311689 in words is "thirty-one million, three hundred eleven thousand, six hundred eighty-nine".