18018 has 48 divisors (see below), whose sum is σ = 52416. Its totient is φ = 4320.

The previous prime is 18013. The next prime is 18041. The reversal of 18018 is 81081.

It is a happy number.

It is a hoax number, since the sum of its digits (18) coincides with the sum of the digits of its distinct prime factors.

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

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18013) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1380 + ... + 1392.

It is an arithmetic number, because the mean of its divisors is an integer number (1092).

2¹⁸⁰¹⁸ is an apocalyptic number.

18018 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 18018, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26208).

18018 is an abundant number, since it is smaller than the sum of its proper divisors (34398).

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

18018 is a wasteful number, since it uses less digits than its factorization.

18018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39 (or 36 counting only the distinct ones).

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

The square root of 18018 is about 134.2311439272. The cubic root of 18018 is about 26.2161468364.

18018 divided by its sum of digits (18) gives a palindrome (1001).

Adding to 18018 its reverse (81081), we get a palindrome (99099).

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

The spelling of 18018 in words is "eighteen thousand, eighteen".