31691593 has 4 divisors (see below), whose sum is σ = 31747860. Its totient is φ = 31635328.

The previous prime is 31691557. The next prime is 31691609. The reversal of 31691593 is 39519613.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 22155849 + 9535744 = 4707^2 + 3088^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31691593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31691533) 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 3 ways as a sum of consecutive naturals, for example, 27280 + ... + 28417.

It is an arithmetic number, because the mean of its divisors is an integer number (7936965).

Almost surely, 2^31691593 is an apocalyptic number.

It is an amenable number.

31691593 is a deficient number, since it is larger than the sum of its proper divisors (56267).

31691593 is an equidigital number, since it uses as much as digits as its factorization.

31691593 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56266.

The product of its digits is 21870, while the sum is 37.

The square root of 31691593 is about 5629.5286658831. The cubic root of 31691593 is about 316.4569878167.

The spelling of 31691593 in words is "thirty-one million, six hundred ninety-one thousand, five hundred ninety-three".