31911689 has 2 divisors, whose sum is σ = 31911690. Its totient is φ = 31911688.

The previous prime is 31911673. The next prime is 31911701. The reversal of 31911689 is 98611913.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19891600 + 12020089 = 4460^2 + 3467^2 .

It is an emirp because it is prime and its reverse (98611913) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31911689 - 2⁴ = 31911673 is a prime.

It is not a weakly prime, because it can be changed into another prime (31911619) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15955844 + 15955845.

It is an arithmetic number, because the mean of its divisors is an integer number (15955845).

Almost surely, 2^31911689 is an apocalyptic number.

It is an amenable number.

31911689 is a deficient number, since it is larger than the sum of its proper divisors (1).

31911689 is an equidigital number, since it uses as much as digits as its factorization.

31911689 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11664, while the sum is 38.

The square root of 31911689 is about 5649.0431933204. The cubic root of 31911689 is about 317.1878892907.

The spelling of 31911689 in words is "thirty-one million, nine hundred eleven thousand, six hundred eighty-nine".