23165981 has 2 divisors, whose sum is σ = 23165982. Its totient is φ = 23165980.

The previous prime is 23165977. The next prime is 23165993. The reversal of 23165981 is 18956132.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 22477081 + 688900 = 4741^2 + 830^2 .

It is a cyclic number.

It is not a de Polignac number, because 23165981 - 2² = 23165977 is a prime.

It is a super-2 number, since 2×23165981² = 1073325351384722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (23165941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11582990 + 11582991.

It is an arithmetic number, because the mean of its divisors is an integer number (11582991).

Almost surely, 2^23165981 is an apocalyptic number.

It is an amenable number.

23165981 is a deficient number, since it is larger than the sum of its proper divisors (1).

23165981 is an equidigital number, since it uses as much as digits as its factorization.

23165981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12960, while the sum is 35.

The square root of 23165981 is about 4813.1051307862. The cubic root of 23165981 is about 285.0691573220.

The spelling of 23165981 in words is "twenty-three million, one hundred sixty-five thousand, nine hundred eighty-one".