18813909 has 4 divisors (see below), whose sum is σ = 25085216. Its totient is φ = 12542604.

The previous prime is 18813863. The next prime is 18813913. The reversal of 18813909 is 90931881.

It is a happy number.

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 18813909 - 2²⁰ = 17765333 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18813989) 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, 3135649 + ... + 3135654.

It is an arithmetic number, because the mean of its divisors is an integer number (6271304).

Almost surely, 2^18813909 is an apocalyptic number.

It is an amenable number.

18813909 is a deficient number, since it is larger than the sum of its proper divisors (6271307).

18813909 is an equidigital number, since it uses as much as digits as its factorization.

18813909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6271306.

The product of its (nonzero) digits is 15552, while the sum is 39.

The square root of 18813909 is about 4337.5003170029. The cubic root of 18813909 is about 265.9661375478.

The spelling of 18813909 in words is "eighteen million, eight hundred thirteen thousand, nine hundred nine".