31212320113 has 4 divisors (see below), whose sum is σ = 33613267828. Its totient is φ = 28811372400.

The previous prime is 31212320101. The next prime is 31212320137. The reversal of 31212320113 is 31102321213.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 31102321213 = 74143 ⋅419491.

It can be written as a sum of positive squares in 2 ways, for example, as 18022257009 + 13190063104 = 134247^2 + 114848^2 .

It is a cyclic number.

It is not a de Polignac number, because 31212320113 - 2⁹ = 31212319601 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31212300113) 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, 1200473838 + ... + 1200473863.

It is an arithmetic number, because the mean of its divisors is an integer number (8403316957).

Almost surely, 2^31212320113 is an apocalyptic number.

It is an amenable number.

31212320113 is a deficient number, since it is larger than the sum of its proper divisors (2400947715).

31212320113 is a wasteful number, since it uses less digits than its factorization.

31212320113 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2400947714.

The product of its (nonzero) digits is 216, while the sum is 19.

Adding to 31212320113 its reverse (31102321213), we get a palindrome (62314641326).

The spelling of 31212320113 in words is "thirty-one billion, two hundred twelve million, three hundred twenty thousand, one hundred thirteen".