23721865 has 4 divisors (see below), whose sum is σ = 28466244. Its totient is φ = 18977488.

The previous prime is 23721857. The next prime is 23721869. The reversal of 23721865 is 56812732.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4194304 + 19527561 = 2048^2 + 4419^2 .

It is a cyclic number.

It is not a de Polignac number, because 23721865 - 2³ = 23721857 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 23721865.

It is not an unprimeable number, because it can be changed into a prime (23721869) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2372182 + ... + 2372191.

It is an arithmetic number, because the mean of its divisors is an integer number (7116561).

Almost surely, 2^23721865 is an apocalyptic number.

It is an amenable number.

23721865 is a deficient number, since it is larger than the sum of its proper divisors (4744379).

23721865 is an equidigital number, since it uses as much as digits as its factorization.

23721865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4744378.

The product of its digits is 20160, while the sum is 34.

The square root of 23721865 is about 4870.5097269177. The cubic root of 23721865 is about 287.3313036800.

The spelling of 23721865 in words is "twenty-three million, seven hundred twenty-one thousand, eight hundred sixty-five".