18109 has 8 divisors (see below), whose sum is σ = 22400. Its totient is φ = 14256.

The previous prime is 18097. The next prime is 18119. The reversal of 18109 is 90181.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18109 - 2⁵ = 18077 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a plaindrome in base 16.

It is a nialpdrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18119) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9 + ... + 190.

It is an arithmetic number, because the mean of its divisors is an integer number (2800).

2¹⁸¹⁰⁹ is an apocalyptic number.

It is an amenable number.

18109 is a deficient number, since it is larger than the sum of its proper divisors (4291).

18109 is a wasteful number, since it uses less digits than its factorization.

18109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 219.

The product of its (nonzero) digits is 72, while the sum is 19.

The square root of 18109 is about 134.5696845504. The cubic root of 18109 is about 26.2602076703.

Adding to 18109 its product of nonzero digits (72), we get a palindrome (18181).

It can be divided in two parts, 1810 and 9, that multiplied together give a triangular number (16290 = T₁₈₀).

The spelling of 18109 in words is "eighteen thousand, one hundred nine".