Is 218 a prime number? What are the divisors of 218?

## Parity of 218

218 is an even number, because it is evenly divisible by 2: 218 / 2 = 109.

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## Is 218 a perfect square number?

A number is a perfect square (or a square number) if its square root is an integer; that is to say, it is the product of an integer with itself. Here, the square root of 218 is about 14.765.

Thus, the square root of 218 is not an integer, and therefore 218 is not a square number.

## What is the square number of 218?

The square of a number (here 218) is the result of the product of this number (218) by itself (i.e., 218 × 218); the square of 218 is sometimes called "raising 218 to the power 2", or "218 squared".

The square of 218 is 47 524 because 218 × 218 = 2182 = 47 524.

As a consequence, 218 is the square root of 47 524.

## Number of digits of 218

218 is a number with 3 digits.

## What are the multiples of 218?

The multiples of 218 are all integers evenly divisible by 218, that is all numbers such that the remainder of the division by 218 is zero. There are infinitely many multiples of 218. The smallest multiples of 218 are:

• 0: indeed, 0 is divisible by any natural number, and it is thus a multiple of 218 too, since 0 × 218 = 0
• 218: indeed, 218 is a multiple of itself, since 218 is evenly divisible by 218 (we have 218 / 218 = 1, so the remainder of this division is indeed zero)
• 436: indeed, 436 = 218 × 2
• 654: indeed, 654 = 218 × 3
• 872: indeed, 872 = 218 × 4
• 1 090: indeed, 1 090 = 218 × 5
• etc.

## How to determine whether an integer is a prime number?

To determine the primality of a number, several algorithms can be used. The most naive technique is to test all divisors strictly smaller to the number of which we want to determine the primality (here 218). First, we can eliminate all even numbers greater than 2 (and hence 4, 6, 8…). Then, we can stop this check when we reach the square root of the number of which we want to determine the primality (here the square root is about 14.765). Historically, the sieve of Eratosthenes (dating from the Greek mathematics) implements this technique in a relatively efficient manner.

More modern techniques include the sieve of Atkin, probabilistic algorithms, and the cyclotomic AKS test.

## Numbers near 218

• Preceding numbers: …216, 217
• Following numbers: 219, 220

### Nearest numbers from 218

• Preceding prime number: 211
• Following prime number: 223
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