18520 has 16 divisors (see below), whose sum is σ = 41760. Its totient is φ = 7392.

The previous prime is 18517. The next prime is 18521. The reversal of 18520 is 2581.

It is a happy number.

It is a nialpdrome in base 12.

It is a junction number, because it is equal to n+sod(n) for n = 18494 and 18503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18521) 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, 192 + ... + 271.

It is an arithmetic number, because the mean of its divisors is an integer number (2610).

2¹⁸⁵²⁰ is an apocalyptic number.

18520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18520 is an abundant number, since it is smaller than the sum of its proper divisors (23240).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20880).

18520 is a wasteful number, since it uses less digits than its factorization.

18520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 474 (or 470 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 16.

The square root of 18520 is about 136.0882066896. The cubic root of 18520 is about 26.4573896922.

The spelling of 18520 in words is "eighteen thousand, five hundred twenty".