13909 has 4 divisors (see below), whose sum is σ = 15904.
Its totient is φ = 11916.
The previous prime is 13907. The next prime is 13913. The reversal of 13909 is 90931.
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 a cyclic number.
It is not a de Polignac number, because 13909 - 21 = 13907 is a prime.
It is a self number, because there is not a number n which added to its sum of digits gives 13909.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (13901) 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, 987 + ... + 1000.
It is an arithmetic number, because the mean of its divisors is an integer number (3976).
213909 is an apocalyptic number.
It is an amenable number.
13909 is a deficient number, since it is larger than the sum of its proper divisors (1995).
13909 is an equidigital number, since it uses as much as digits as its factorization.
13909 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 1994.
The product of its (nonzero) digits is 243, while the sum is 22.
The square root of 13909 is about 117.9364235510.
The cubic root of 13909 is about 24.0490893396.
Adding to 13909 its sum of digits (22), we get a palindrome (13931).
The spelling of 13909 in words is "thirteen thousand, nine hundred nine".