13565 has 4 divisors (see below), whose sum is σ = 16284. Its totient is φ = 10848.

The previous prime is 13553. The next prime is 13567. The reversal of 13565 is 56531.

13565 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

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 10201 + 3364 = 101^2 + 58^2 .

It is a cyclic number.

It is not a de Polignac number, because 13565 - 2⁸ = 13309 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13567) 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, 1352 + ... + 1361.

It is an arithmetic number, because the mean of its divisors is an integer number (4071).

2¹³⁵⁶⁵ is an apocalyptic number.

It is an amenable number.

13565 is a deficient number, since it is larger than the sum of its proper divisors (2719).

13565 is an equidigital number, since it uses as much as digits as its factorization.

13565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2718.

The product of its digits is 450, while the sum is 20.

The square root of 13565 is about 116.4688799637. The cubic root of 13565 is about 23.8491698205.

The spelling of 13565 in words is "thirteen thousand, five hundred sixty-five".