218172 has 12 divisors (see below), whose sum is σ = 509096. Its totient is φ = 72720.

The previous prime is 218171. The next prime is 218191. The reversal of 218172 is 271812.

218172 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a plaindrome in base 15.

It is a nialpdrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218171) 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, 9079 + ... + 9102.

2²¹⁸¹⁷² is an apocalyptic number.

It is an amenable number.

218172 is an abundant number, since it is smaller than the sum of its proper divisors (290924).

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

218172 is a wasteful number, since it uses less digits than its factorization.

218172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18188 (or 18186 counting only the distinct ones).

The product of its digits is 224, while the sum is 21.

The square root of 218172 is about 467.0888566429. The cubic root of 218172 is about 60.2004407572.

Adding to 218172 its reverse (271812), we get a palindrome (489984).

It can be divided in two parts, 21817 and 2, that multiplied together give a palindrome (43634).

The spelling of 218172 in words is "two hundred eighteen thousand, one hundred seventy-two".