13557209 has 4 divisors (see below), whose sum is σ = 13593360. Its totient is φ = 13521060.

The previous prime is 13557191. The next prime is 13557217. The reversal of 13557209 is 90275531.

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, and also an emirpimes, since its reverse is a distinct semiprime: 90275531 = 83 ⋅1087657.

It is a cyclic number.

It is not a de Polignac number, because 13557209 - 2²⁰ = 12508633 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (13557289) 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, 17507 + ... + 18264.

It is an arithmetic number, because the mean of its divisors is an integer number (3398340).

Almost surely, 2^13557209 is an apocalyptic number.

It is an amenable number.

13557209 is a deficient number, since it is larger than the sum of its proper divisors (36151).

13557209 is an equidigital number, since it uses as much as digits as its factorization.

13557209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36150.

The product of its (nonzero) digits is 9450, while the sum is 32.

The square root of 13557209 is about 3682.0115426218. The cubic root of 13557209 is about 238.4460305638.

The spelling of 13557209 in words is "thirteen million, five hundred fifty-seven thousand, two hundred nine".