31231131233213 has 4 divisors (see below), whose sum is σ = 31231153857948. Its totient is φ = 31231108608480.

The previous prime is 31231131233209. The next prime is 31231131233227. The reversal of 31231131233213 is 31233213113213.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 19155485383204 + 12075645850009 = 4376698^2 + 3475003^2 .

It is a cyclic number.

It is not a de Polignac number, because 31231131233213 - 2² = 31231131233209 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 (31231131233293) 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, 9097178 + ... + 12050763.

It is an arithmetic number, because the mean of its divisors is an integer number (7807788464487).

Almost surely, 2^{31231131233213} is an apocalyptic number.

It is an amenable number.

31231131233213 is a deficient number, since it is larger than the sum of its proper divisors (22624735).

31231131233213 is a wasteful number, since it uses less digits than its factorization.

31231131233213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22624734.

The product of its digits is 5832, while the sum is 29.

Adding to 31231131233213 its reverse (31233213113213), we get a palindrome (62464344346426).

The spelling of 31231131233213 in words is "thirty-one trillion, two hundred thirty-one billion, one hundred thirty-one million, two hundred thirty-three thousand, two hundred thirteen".