13856209 has 4 divisors (see below), whose sum is σ = 14091120. Its totient is φ = 13621300.

The previous prime is 13856177. The next prime is 13856221. The reversal of 13856209 is 90265831.

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 13856209 - 2⁵ = 13856177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13856279) 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, 117367 + ... + 117484.

It is an arithmetic number, because the mean of its divisors is an integer number (3522780).

Almost surely, 2^13856209 is an apocalyptic number.

It is an amenable number.

13856209 is a deficient number, since it is larger than the sum of its proper divisors (234911).

13856209 is an equidigital number, since it uses as much as digits as its factorization.

13856209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 234910.

The product of its (nonzero) digits is 12960, while the sum is 34.

The square root of 13856209 is about 3722.3929131676. The cubic root of 13856209 is about 240.1862501006.

The spelling of 13856209 in words is "thirteen million, eight hundred fifty-six thousand, two hundred nine".