23616721 has 2 divisors, whose sum is σ = 23616722. Its totient is φ = 23616720.

The previous prime is 23616713. The next prime is 23616727. The reversal of 23616721 is 12761632.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12327121 + 11289600 = 3511^2 + 3360^2 .

It is a cyclic number.

It is not a de Polignac number, because 23616721 - 2³ = 23616713 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a self number, because there is not a number n which added to its sum of digits gives 23616721.

It is not a weakly prime, because it can be changed into another prime (23616727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11808360 + 11808361.

It is an arithmetic number, because the mean of its divisors is an integer number (11808361).

Almost surely, 2^23616721 is an apocalyptic number.

It is an amenable number.

23616721 is a deficient number, since it is larger than the sum of its proper divisors (1).

23616721 is an equidigital number, since it uses as much as digits as its factorization.

23616721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3024, while the sum is 28.

The square root of 23616721 is about 4859.7037975580. The cubic root of 23616721 is about 286.9061557067.

The spelling of 23616721 in words is "twenty-three million, six hundred sixteen thousand, seven hundred twenty-one".