23615981 has 2 divisors, whose sum is σ = 23615982. Its totient is φ = 23615980.

The previous prime is 23615951. The next prime is 23616001. The reversal of 23615981 is 18951632.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20160100 + 3455881 = 4490^2 + 1859^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-23615981 is a prime.

It is a super-2 number, since 2×23615981² = 1115429117184722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (23615951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11807990 + 11807991.

It is an arithmetic number, because the mean of its divisors is an integer number (11807991).

Almost surely, 2^23615981 is an apocalyptic number.

It is an amenable number.

23615981 is a deficient number, since it is larger than the sum of its proper divisors (1).

23615981 is an equidigital number, since it uses as much as digits as its factorization.

23615981 is an evil number, because the sum of its binary digits is even.

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

The square root of 23615981 is about 4859.6276606341. The cubic root of 23615981 is about 286.9031590619.

The spelling of 23615981 in words is "twenty-three million, six hundred fifteen thousand, nine hundred eighty-one".