218231 has 4 divisors (see below), whose sum is σ = 235032. Its totient is φ = 201432.

The previous prime is 218227. The next prime is 218233. The reversal of 218231 is 132812.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 218231 - 2² = 218227 is a prime.

It is a super-2 number, since 2×218231² = 95249538722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218233) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8381 + ... + 8406.

It is an arithmetic number, because the mean of its divisors is an integer number (58758).

2²¹⁸²³¹ is an apocalyptic number.

218231 is a deficient number, since it is larger than the sum of its proper divisors (16801).

218231 is a wasteful number, since it uses less digits than its factorization.

218231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16800.

The product of its digits is 96, while the sum is 17.

The square root of 218231 is about 467.1520095215. The cubic root of 218231 is about 60.2058669131.

The spelling of 218231 in words is "two hundred eighteen thousand, two hundred thirty-one".