Is 198 a prime number? What are the divisors of 198?

## Parity of 198

198 is an even number, because it is evenly divisible by 2: 198 / 2 = 99.

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## Is 198 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 198 is about 14.071.

Thus, the square root of 198 is not an integer, and therefore 198 is not a square number.

## What is the square number of 198?

The square of a number (here 198) is the result of the product of this number (198) by itself (i.e., 198 × 198); the square of 198 is sometimes called "raising 198 to the power 2", or "198 squared".

The square of 198 is 39 204 because 198 × 198 = 1982 = 39 204.

As a consequence, 198 is the square root of 39 204.

## Number of digits of 198

198 is a number with 3 digits.

## What are the multiples of 198?

The multiples of 198 are all integers evenly divisible by 198, that is all numbers such that the remainder of the division by 198 is zero. There are infinitely many multiples of 198. The smallest multiples of 198 are:

• 0: indeed, 0 is divisible by any natural number, and it is thus a multiple of 198 too, since 0 × 198 = 0
• 198: indeed, 198 is a multiple of itself, since 198 is evenly divisible by 198 (we have 198 / 198 = 1, so the remainder of this division is indeed zero)
• 396: indeed, 396 = 198 × 2
• 594: indeed, 594 = 198 × 3
• 792: indeed, 792 = 198 × 4
• 990: indeed, 990 = 198 × 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 198). 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 14.071). 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 198

• Preceding numbers: …196, 197
• Following numbers: 199, 200

### Nearest numbers from 198

• Preceding prime number: 197
• Following prime number: 199
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