23661565 has 4 divisors (see below), whose sum is σ = 28393884. Its totient is φ = 18929248.

The previous prime is 23661559. The next prime is 23661577. The reversal of 23661565 is 56516632.

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 4485924 + 19175641 = 2118^2 + 4379^2 .

It is a cyclic number.

It is not a de Polignac number, because 23661565 - 2¹³ = 23653373 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 23661565.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2366152 + ... + 2366161.

It is an arithmetic number, because the mean of its divisors is an integer number (7098471).

Almost surely, 2^23661565 is an apocalyptic number.

It is an amenable number.

23661565 is a deficient number, since it is larger than the sum of its proper divisors (4732319).

23661565 is an equidigital number, since it uses as much as digits as its factorization.

23661565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4732318.

The product of its digits is 32400, while the sum is 34.

The square root of 23661565 is about 4864.3154708551. The cubic root of 23661565 is about 287.0876356673.

The spelling of 23661565 in words is "twenty-three million, six hundred sixty-one thousand, five hundred sixty-five".