18506 has 8 divisors (see below), whose sum is σ = 29280. Its totient is φ = 8748.

The previous prime is 18503. The next prime is 18517. The reversal of 18506 is 60581.

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

It is a Curzon number.

It is a nialpdrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18503) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 206 + ... + 281.

It is an arithmetic number, because the mean of its divisors is an integer number (3660).

2¹⁸⁵⁰⁶ is an apocalyptic number.

18506 is a deficient number, since it is larger than the sum of its proper divisors (10774).

18506 is a wasteful number, since it uses less digits than its factorization.

18506 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 508.

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 18506 is about 136.0367597379. The cubic root of 18506 is about 26.4507212828.

The spelling of 18506 in words is "eighteen thousand, five hundred six".