31231212013 has 4 divisors (see below), whose sum is σ = 31233017088. Its totient is φ = 31229406940.

The previous prime is 31231211959. The next prime is 31231212037. The reversal of 31231212013 is 31021213213.

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: 31021213213 = 28069 ⋅1105177.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31231212013 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31231212083) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 876331 + ... + 911272.

It is an arithmetic number, because the mean of its divisors is an integer number (7808254272).

Almost surely, 2^31231212013 is an apocalyptic number.

It is an amenable number.

31231212013 is a deficient number, since it is larger than the sum of its proper divisors (1805075).

31231212013 is a wasteful number, since it uses less digits than its factorization.

31231212013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1805074.

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

Adding to 31231212013 its reverse (31021213213), we get a palindrome (62252425226).

The spelling of 31231212013 in words is "thirty-one billion, two hundred thirty-one million, two hundred twelve thousand, thirteen".