18180 has 36 divisors (see below), whose sum is σ = 55692. Its totient is φ = 4800.

The previous prime is 18169. The next prime is 18181. The reversal of 18180 is 8181.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 12996 + 5184 = 114^2 + 72^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (18).

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 (18181) by changing a digit.

18180 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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 11 ways as a sum of consecutive naturals, for example, 130 + ... + 230.

It is an arithmetic number, because the mean of its divisors is an integer number (1547).

2¹⁸¹⁸⁰ is an apocalyptic number.

18180 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 18180, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27846).

18180 is an abundant number, since it is smaller than the sum of its proper divisors (37512).

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

18180 is a wasteful number, since it uses less digits than its factorization.

18180 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 116 (or 111 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

The square root of 18180 is about 134.8332303255. The cubic root of 18180 is about 26.2944824021.

Subtracting from 18180 its reverse (8181), we obtain a palindrome (9999).

It can be divided in two parts, 18 and 180, that multiplied together give a triangular number (3240 = T₈₀).

The spelling of 18180 in words is "eighteen thousand, one hundred eighty".