Is 165 a prime number? What are the divisors of 165?

## Parity of 165

165 is an odd number, because it is not evenly divisible by 2.

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## Is 165 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 165 is about 12.845.

Thus, the square root of 165 is not an integer, and therefore 165 is not a square number.

## What is the square number of 165?

The square of a number (here 165) is the result of the product of this number (165) by itself (i.e., 165 × 165); the square of 165 is sometimes called "raising 165 to the power 2", or "165 squared".

The square of 165 is 27 225 because 165 × 165 = 1652 = 27 225.

As a consequence, 165 is the square root of 27 225.

## Number of digits of 165

165 is a number with 3 digits.

## What are the multiples of 165?

The multiples of 165 are all integers evenly divisible by 165, that is all numbers such that the remainder of the division by 165 is zero. There are infinitely many multiples of 165. The smallest multiples of 165 are:

• 0: indeed, 0 is divisible by any natural number, and it is thus a multiple of 165 too, since 0 × 165 = 0
• 165: indeed, 165 is a multiple of itself, since 165 is evenly divisible by 165 (we have 165 / 165 = 1, so the remainder of this division is indeed zero)
• 330: indeed, 330 = 165 × 2
• 495: indeed, 495 = 165 × 3
• 660: indeed, 660 = 165 × 4
• 825: indeed, 825 = 165 × 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 165). 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 12.845). 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 165

• Preceding numbers: …163, 164
• Following numbers: 166, 167

### Nearest numbers from 165

• Preceding prime number: 163
• Following prime number: 167
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