231941981 has 2 divisors, whose sum is σ = 231941982. Its totient is φ = 231941980.

The previous prime is 231941977. The next prime is 231942049. The reversal of 231941981 is 189149132.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 231192025 + 749956 = 15205^2 + 866^2 .

It is a cyclic number.

It is not a de Polignac number, because 231941981 - 2² = 231941977 is a prime.

It is a super-2 number, since 2×231941981² = 107594165100408722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (231041981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115970990 + 115970991.

It is an arithmetic number, because the mean of its divisors is an integer number (115970991).

Almost surely, 2^231941981 is an apocalyptic number.

It is an amenable number.

231941981 is a deficient number, since it is larger than the sum of its proper divisors (1).

231941981 is an equidigital number, since it uses as much as digits as its factorization.

231941981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15552, while the sum is 38.

The square root of 231941981 is about 15229.6415256565. The cubic root of 231941981 is about 614.4121388121.

The spelling of 231941981 in words is "two hundred thirty-one million, nine hundred forty-one thousand, nine hundred eighty-one".