218404 has 6 divisors (see below), whose sum is σ = 382214. Its totient is φ = 109200.

The previous prime is 218401. The next prime is 218417. The reversal of 218404 is 404812.

218404 is nontrivially palindromic in base 6.

It can be written as a sum of positive squares in only one way, i.e., 129600 + 88804 = 360^2 + 298^2 .

It is not an unprimeable number, because it can be changed into a prime (218401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27297 + ... + 27304.

2²¹⁸⁴⁰⁴ is an apocalyptic number.

It is an amenable number.

218404 is a deficient number, since it is larger than the sum of its proper divisors (163810).

218404 is a wasteful number, since it uses less digits than its factorization.

218404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54605 (or 54603 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 19.

The square root of 218404 is about 467.3371374072. The cubic root of 218404 is about 60.2217718699.

The spelling of 218404 in words is "two hundred eighteen thousand, four hundred four".