218388 has 12 divisors (see below), whose sum is σ = 509600. Its totient is φ = 72792.

The previous prime is 218381. The next prime is 218389. The reversal of 218388 is 883812.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 218388.

It is not an unprimeable number, because it can be changed into a prime (218381) by changing a digit.

218388 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 3 ways as a sum of consecutive naturals, for example, 9088 + ... + 9111.

2²¹⁸³⁸⁸ is an apocalyptic number.

It is an amenable number.

218388 is an abundant number, since it is smaller than the sum of its proper divisors (291212).

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

218388 is a wasteful number, since it uses less digits than its factorization.

218388 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18206 (or 18204 counting only the distinct ones).

The product of its digits is 3072, while the sum is 30.

The square root of 218388 is about 467.3200188308. The cubic root of 218388 is about 60.2203012438.

It can be divided in two parts, 218 and 388, that added together give a palindrome (606).

The spelling of 218388 in words is "two hundred eighteen thousand, three hundred eighty-eight".