218543 has 4 divisors (see below), whose sum is σ = 235368. Its totient is φ = 201720.

The previous prime is 218531. The next prime is 218549. The reversal of 218543 is 345812.

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 218543 - 2⁴ = 218527 is a prime.

It is a super-2 number, since 2×218543² = 95522085698, which contains 22 as substring.

It is an Ulam number.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218549) 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, 8393 + ... + 8418.

It is an arithmetic number, because the mean of its divisors is an integer number (58842).

2²¹⁸⁵⁴³ is an apocalyptic number.

218543 is a deficient number, since it is larger than the sum of its proper divisors (16825).

218543 is a wasteful number, since it uses less digits than its factorization.

218543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16824.

The product of its digits is 960, while the sum is 23.

The square root of 218543 is about 467.4858286622. The cubic root of 218543 is about 60.2345449130.

The spelling of 218543 in words is "two hundred eighteen thousand, five hundred forty-three".