31816661813 has 4 divisors (see below), whose sum is σ = 31821423648. Its totient is φ = 31811899980.

The previous prime is 31816661809. The next prime is 31816661837.

31816661813 is nontrivially palindromic in base 10.

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 a cyclic number.

It is not a de Polignac number, because 31816661813 - 2² = 31816661809 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 (31816661873) 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, 2370881 + ... + 2384262.

It is an arithmetic number, because the mean of its divisors is an integer number (7955355912).

Almost surely, 2^31816661813 is an apocalyptic number.

It is an amenable number.

31816661813 is a deficient number, since it is larger than the sum of its proper divisors (4761835).

31816661813 is an equidigital number, since it uses as much as digits as its factorization.

31816661813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4761834.

The product of its digits is 124416, while the sum is 44.

The spelling of 31816661813 in words is "thirty-one billion, eight hundred sixteen million, six hundred sixty-one thousand, eight hundred thirteen".