31691093 has 6 divisors (see below), whose sum is σ = 36865206. Its totient is φ = 27163752.

The previous prime is 31691057. The next prime is 31691117. The reversal of 31691093 is 39019613.

It can be written as a sum of positive squares in only one way, i.e., 20448484 + 11242609 = 4522^2 + 3353^2 .

It is not a de Polignac number, because 31691093 - 2²² = 27496789 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31691053) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 323330 + ... + 323427.

It is an arithmetic number, because the mean of its divisors is an integer number (6144201).

Almost surely, 2^31691093 is an apocalyptic number.

It is an amenable number.

31691093 is a deficient number, since it is larger than the sum of its proper divisors (5174113).

31691093 is an equidigital number, since it uses as much as digits as its factorization.

31691093 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 646771 (or 646764 counting only the distinct ones).

The product of its (nonzero) digits is 4374, while the sum is 32.

The square root of 31691093 is about 5629.4842570168. The cubic root of 31691093 is about 316.4553235548.

The spelling of 31691093 in words is "thirty-one million, six hundred ninety-one thousand, ninety-three".