31139165 has 4 divisors (see below), whose sum is σ = 37367004. Its totient is φ = 24911328.

The previous prime is 31139149. The next prime is 31139177. The reversal of 31139165 is 56193113.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 56193113 = 139 ⋅404267.

It can be written as a sum of positive squares in 2 ways, for example, as 10582009 + 20557156 = 3253^2 + 4534^2 .

It is a cyclic number.

It is not a de Polignac number, because 31139165 - 2⁴ = 31139149 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3113912 + ... + 3113921.

It is an arithmetic number, because the mean of its divisors is an integer number (9341751).

Almost surely, 2^31139165 is an apocalyptic number.

It is an amenable number.

31139165 is a deficient number, since it is larger than the sum of its proper divisors (6227839).

31139165 is an equidigital number, since it uses as much as digits as its factorization.

31139165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6227838.

The product of its digits is 2430, while the sum is 29.

The square root of 31139165 is about 5580.2477543564. The cubic root of 31139165 is about 314.6074390935.

The spelling of 31139165 in words is "thirty-one million, one hundred thirty-nine thousand, one hundred sixty-five".