31123121313 has 4 divisors (see below), whose sum is σ = 41497495088. Its totient is φ = 20748747540.

The previous prime is 31123121303. The next prime is 31123121327. The reversal of 31123121313 is 31312132113.

It is a happy number.

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.

It is not a de Polignac number, because 31123121313 - 2²² = 31118927009 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 31123121313.

It is not an unprimeable number, because it can be changed into a prime (31123121303) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5187186883 + ... + 5187186888.

It is an arithmetic number, because the mean of its divisors is an integer number (10374373772).

Almost surely, 2^31123121313 is an apocalyptic number.

It is an amenable number.

31123121313 is a deficient number, since it is larger than the sum of its proper divisors (10374373775).

31123121313 is a wasteful number, since it uses less digits than its factorization.

31123121313 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10374373774.

The product of its digits is 324, while the sum is 21.

Adding to 31123121313 its reverse (31312132113), we get a palindrome (62435253426).

The spelling of 31123121313 in words is "thirty-one billion, one hundred twenty-three million, one hundred twenty-one thousand, three hundred thirteen".