2331311981 has 2 divisors, whose sum is σ = 2331311982. Its totient is φ = 2331311980.

The previous prime is 2331311971. The next prime is 2331312043. The reversal of 2331311981 is 1891131332.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1694557225 + 636754756 = 41165^2 + 25234^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2331311981 is a prime.

It is a super-2 number, since 2×2331311981² = 10870031105508288722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2331311911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1165655990 + 1165655991.

It is an arithmetic number, because the mean of its divisors is an integer number (1165655991).

Almost surely, 2^2331311981 is an apocalyptic number.

It is an amenable number.

2331311981 is a deficient number, since it is larger than the sum of its proper divisors (1).

2331311981 is an equidigital number, since it uses as much as digits as its factorization.

2331311981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3888, while the sum is 32.

The square root of 2331311981 is about 48283.6616362098. The cubic root of 2331311981 is about 1325.9692883347.

The spelling of 2331311981 in words is "two billion, three hundred thirty-one million, three hundred eleven thousand, nine hundred eighty-one".