218218 has 32 divisors (see below), whose sum is σ = 443520. Its totient is φ = 77760.

The previous prime is 218213. The next prime is 218227. The reversal of 218218 is 812812.

218218 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a plaindrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (218213) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1948 + ... + 2056.

It is an arithmetic number, because the mean of its divisors is an integer number (13860).

2²¹⁸²¹⁸ is an apocalyptic number.

218218 is an abundant number, since it is smaller than the sum of its proper divisors (225302).

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

218218 is a wasteful number, since it uses less digits than its factorization.

218218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 142.

The product of its digits is 256, while the sum is 22.

The square root of 218218 is about 467.1380952138. The cubic root of 218218 is about 60.2046714034.

It can be divided in two parts, 21 and 8218, that multiplied together give a triangular number (172578 = T₅₈₇).

The spelling of 218218 in words is "two hundred eighteen thousand, two hundred eighteen".