31213144836 has 18 divisors (see below), whose sum is σ = 78899893982. Its totient is φ = 10404381600.

The previous prime is 31213144829. The next prime is 31213144841. The reversal of 31213144836 is 63844131213.

It can be written as a sum of positive squares in only one way, i.e., 23364956736 + 7848188100 = 152856^2 + 88590^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a super-2 number, since 2×31213144836² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 867031801 = 31213144836 / (3 + 1 + 2 + 1 + 3 + 1 + 4 + 4 + 8 + 3 + 6).

It is a self number, because there is not a number n which added to its sum of digits gives 31213144836.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 433515865 + ... + 433515936.

Almost surely, 2^31213144836 is an apocalyptic number.

31213144836 is a gapful number since it is divisible by the number (36) formed by its first and last digit.

It is an amenable number.

31213144836 is an abundant number, since it is smaller than the sum of its proper divisors (47686749146).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31213144836 is a wasteful number, since it uses less digits than its factorization.

31213144836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 867031811 (or 867031806 counting only the distinct ones).

The product of its digits is 41472, while the sum is 36.

The spelling of 31213144836 in words is "thirty-one billion, two hundred thirteen million, one hundred forty-four thousand, eight hundred thirty-six".