31808013 has 4 divisors (see below), whose sum is σ = 42410688. Its totient is φ = 21205340.

The previous prime is 31807991. The next prime is 31808017. The reversal of 31808013 is 31080813.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 31080813 = 3 ⋅10360271.

It is a cyclic number.

It is not a de Polignac number, because 31808013 - 2¹³ = 31799821 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31808017) 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, 5301333 + ... + 5301338.

It is an arithmetic number, because the mean of its divisors is an integer number (10602672).

Almost surely, 2^31808013 is an apocalyptic number.

It is an amenable number.

31808013 is a deficient number, since it is larger than the sum of its proper divisors (10602675).

31808013 is a wasteful number, since it uses less digits than its factorization.

31808013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10602674.

The product of its (nonzero) digits is 576, while the sum is 24.

The square root of 31808013 is about 5639.8593067558. The cubic root of 31808013 is about 316.8440189669.

Adding to 31808013 its reverse (31080813), we get a palindrome (62888826).

The spelling of 31808013 in words is "thirty-one million, eight hundred eight thousand, thirteen".