18309 has 8 divisors (see below), whose sum is σ = 25920. Its totient is φ = 11456.

The previous prime is 18307. The next prime is 18311. The reversal of 18309 is 90381.

It is an interprime number because it is at equal distance from previous prime (18307) and next prime (18311).

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 18309 - 2¹ = 18307 is a prime.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 129 + ... + 230.

It is an arithmetic number, because the mean of its divisors is an integer number (3240).

2¹⁸³⁰⁹ is an apocalyptic number.

It is an amenable number.

18309 is a deficient number, since it is larger than the sum of its proper divisors (7611).

18309 is a wasteful number, since it uses less digits than its factorization.

18309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 379.

The product of its (nonzero) digits is 216, while the sum is 21.

The square root of 18309 is about 135.3107534529. The cubic root of 18309 is about 26.3565285490.

The spelling of 18309 in words is "eighteen thousand, three hundred nine".