18020 has 24 divisors (see below), whose sum is σ = 40824. Its totient is φ = 6656.

The previous prime is 18013. The next prime is 18041. The reversal of 18020 is 2081.

18020 is nontrivially palindromic in base 16.

18020 is an esthetic number in base 4, because in such base its adjacent digits differ by 1.

It can be written as a sum of positive squares in 4 ways, for example, as 5476 + 12544 = 74^2 + 112^2 .

18020 is an undulating number in base 13.

It is a junction number, because it is equal to n+sod(n) for n = 17992 and 18010.

It is an unprimeable number.

18020 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 314 + ... + 366.

It is an arithmetic number, because the mean of its divisors is an integer number (1701).

2¹⁸⁰²⁰ is an apocalyptic number.

18020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20412).

18020 is an abundant number, since it is smaller than the sum of its proper divisors (22804).

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

18020 is a wasteful number, since it uses less digits than its factorization.

18020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79 (or 77 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 18020 is about 134.2385935564. The cubic root of 18020 is about 26.2171167989.

It can be divided in two parts, 180 and 20, that multiplied together give a square (3600 = 60²).

The spelling of 18020 in words is "eighteen thousand, twenty".