20023565 has 4 divisors (see below), whose sum is σ = 24028284. Its totient is φ = 16018848.

The previous prime is 20023561. The next prime is 20023567. The reversal of 20023565 is 56532002.

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 6853924 + 13169641 = 2618^2 + 3629^2 .

It is a cyclic number.

It is not a de Polignac number, because 20023565 - 2² = 20023561 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 20023565.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20023561) 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, 2002352 + ... + 2002361.

It is an arithmetic number, because the mean of its divisors is an integer number (6007071).

Almost surely, 2^20023565 is an apocalyptic number.

It is an amenable number.

20023565 is a deficient number, since it is larger than the sum of its proper divisors (4004719).

20023565 is an equidigital number, since it uses as much as digits as its factorization.

20023565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4004718.

The product of its (nonzero) digits is 1800, while the sum is 23.

The square root of 20023565 is about 4474.7698264827. The cubic root of 20023565 is about 271.5483285682.

Adding to 20023565 its reverse (56532002), we get a palindrome (76555567).

The spelling of 20023565 in words is "twenty million, twenty-three thousand, five hundred sixty-five".