18404 has 12 divisors (see below), whose sum is σ = 33264. Its totient is φ = 8904.

The previous prime is 18401. The next prime is 18413. The reversal of 18404 is 40481.

18404 = T₅ + T₆ + ... + T₄₇.

It is a happy number.

18404 is nontrivially palindromic in base 3.

It is a hoax number, since the sum of its digits (17) coincides with the sum of the digits of its distinct prime factors.

It is a plaindrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (18401) 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, 119 + ... + 225.

It is an arithmetic number, because the mean of its divisors is an integer number (2772).

2¹⁸⁴⁰⁴ is an apocalyptic number.

It is an amenable number.

18404 is a deficient number, since it is larger than the sum of its proper divisors (14860).

18404 is a wasteful number, since it uses less digits than its factorization.

18404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154 (or 152 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

The square root of 18404 is about 135.6613430569. The cubic root of 18404 is about 26.4020353497.

Adding to 18404 its reverse (40481), we get a palindrome (58885).

The spelling of 18404 in words is "eighteen thousand, four hundred four".