18288409 has 4 divisors (see below), whose sum is σ = 18411300. Its totient is φ = 18165520.

The previous prime is 18288383. The next prime is 18288443. The reversal of 18288409 is 90488281.

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 9455625 + 8832784 = 3075^2 + 2972^2 .

It is a cyclic number.

It is not a de Polignac number, because 18288409 - 2⁹ = 18287897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18288449) 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, 61222 + ... + 61519.

It is an arithmetic number, because the mean of its divisors is an integer number (4602825).

Almost surely, 2^18288409 is an apocalyptic number.

It is an amenable number.

18288409 is a deficient number, since it is larger than the sum of its proper divisors (122891).

18288409 is a wasteful number, since it uses less digits than its factorization.

18288409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 122890.

The product of its (nonzero) digits is 36864, while the sum is 40.

The square root of 18288409 is about 4276.4949432918. The cubic root of 18288409 is about 263.4664432349.

The spelling of 18288409 in words is "eighteen million, two hundred eighty-eight thousand, four hundred nine".