23638721 has 8 divisors (see below), whose sum is σ = 25260840. Its totient is φ = 22042368.

The previous prime is 23638711. The next prime is 23638751. The reversal of 23638721 is 12783632.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 9388096 + 14250625 = 3064^2 + 3775^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-23638721 is a prime.

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

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (23638711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4526 + ... + 8231.

It is an arithmetic number, because the mean of its divisors is an integer number (3157605).

Almost surely, 2^23638721 is an apocalyptic number.

It is an amenable number.

23638721 is a deficient number, since it is larger than the sum of its proper divisors (1622119).

23638721 is a wasteful number, since it uses less digits than its factorization.

23638721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12883.

The product of its digits is 12096, while the sum is 32.

The square root of 23638721 is about 4861.9667831033. The cubic root of 23638721 is about 286.9952165673.

The spelling of 23638721 in words is "twenty-three million, six hundred thirty-eight thousand, seven hundred twenty-one".