18089209 has 4 divisors (see below), whose sum is σ = 18147316. Its totient is φ = 18031104.

The previous prime is 18089171. The next prime is 18089221. The reversal of 18089209 is 90298081.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5107600 + 12981609 = 2260^2 + 3603^2 .

It is a cyclic number.

It is not a de Polignac number, because 18089209 - 2⁷ = 18089081 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18089009) 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, 28584 + ... + 29209.

It is an arithmetic number, because the mean of its divisors is an integer number (4536829).

Almost surely, 2^18089209 is an apocalyptic number.

It is an amenable number.

18089209 is a deficient number, since it is larger than the sum of its proper divisors (58107).

18089209 is an equidigital number, since it uses as much as digits as its factorization.

18089209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58106.

The product of its (nonzero) digits is 10368, while the sum is 37.

The square root of 18089209 is about 4253.1410745471. The cubic root of 18089209 is about 262.5063774717.

The spelling of 18089209 in words is "eighteen million, eighty-nine thousand, two hundred nine".