13809 has 4 divisors (see below), whose sum is σ = 18416. Its totient is φ = 9204.

The previous prime is 13807. The next prime is 13829. The reversal of 13809 is 90831.

13809 is nontrivially palindromic in base 7.

13809 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, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 13809 - 2¹ = 13807 is a prime.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13807) 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, 2299 + ... + 2304.

It is an arithmetic number, because the mean of its divisors is an integer number (4604).

2¹³⁸⁰⁹ is an apocalyptic number.

It is an amenable number.

13809 is a deficient number, since it is larger than the sum of its proper divisors (4607).

13809 is an equidigital number, since it uses as much as digits as its factorization.

13809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4606.

The product of its (nonzero) digits is 216, while the sum is 21.

The square root of 13809 is about 117.5117015450. The cubic root of 13809 is about 23.9913163029.

The spelling of 13809 in words is "thirteen thousand, eight hundred nine".