31311043220 has 24 divisors (see below), whose sum is σ = 66431062824. Its totient is φ = 12395298816.

The previous prime is 31311043213. The next prime is 31311043277. The reversal of 31311043220 is 2234011313.

It can be written as a sum of positive squares in 4 ways, for example, as 5916071056 + 25394972164 = 76916^2 + 159358^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 31311043192 and 31311043201.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8067917 + ... + 8071796.

It is an arithmetic number, because the mean of its divisors is an integer number (2767960951).

Almost surely, 2^31311043220 is an apocalyptic number.

It is an amenable number.

31311043220 is an abundant number, since it is smaller than the sum of its proper divisors (35120019604).

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

31311043220 is a wasteful number, since it uses less digits than its factorization.

31311043220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16139819 (or 16139817 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 20.

Adding to 31311043220 its reverse (2234011313), we get a palindrome (33545054533).

The spelling of 31311043220 in words is "thirty-one billion, three hundred eleven million, forty-three thousand, two hundred twenty".