18103209 has 4 divisors (see below), whose sum is σ = 24137616. Its totient is φ = 12068804.

The previous prime is 18103201. The next prime is 18103237. The reversal of 18103209 is 90230181.

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 18103209 - 2³ = 18103201 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18103201) 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, 3017199 + ... + 3017204.

It is an arithmetic number, because the mean of its divisors is an integer number (6034404).

Almost surely, 2^18103209 is an apocalyptic number.

It is an amenable number.

18103209 is a deficient number, since it is larger than the sum of its proper divisors (6034407).

18103209 is an equidigital number, since it uses as much as digits as its factorization.

18103209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6034406.

The product of its (nonzero) digits is 432, while the sum is 24.

The square root of 18103209 is about 4254.7865986439. The cubic root of 18103209 is about 262.5740815854.

The spelling of 18103209 in words is "eighteen million, one hundred three thousand, two hundred nine".