18687 has 4 divisors (see below), whose sum is σ = 24920. Its totient is φ = 12456.

The previous prime is 18679. The next prime is 18691. The reversal of 18687 is 78681.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78681 = 3 ⋅26227.

It is not a de Polignac number, because 18687 - 2³ = 18679 is a prime.

It is a D-number.

It is a Duffinian number.

It is a plaindrome in base 16.

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 (18617) 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, 3112 + ... + 3117.

It is an arithmetic number, because the mean of its divisors is an integer number (6230).

2¹⁸⁶⁸⁷ is an apocalyptic number.

18687 is a deficient number, since it is larger than the sum of its proper divisors (6233).

18687 is an equidigital number, since it uses as much as digits as its factorization.

18687 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6232.

The product of its digits is 2688, while the sum is 30.

The square root of 18687 is about 136.7004023403. The cubic root of 18687 is about 26.5366764023.

The spelling of 18687 in words is "eighteen thousand, six hundred eighty-seven".