Is 855 a prime number? What are the divisors of 855?

## Parity of 855

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

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## Is 855 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 855 is about 29.240.

Thus, the square root of 855 is not an integer, and therefore 855 is not a square number.

## What is the square number of 855?

The square of a number (here 855) is the result of the product of this number (855) by itself (i.e., 855 × 855); the square of 855 is sometimes called "raising 855 to the power 2", or "855 squared".

The square of 855 is 731 025 because 855 × 855 = 8552 = 731 025.

As a consequence, 855 is the square root of 731 025.

## Number of digits of 855

855 is a number with 3 digits.

## What are the multiples of 855?

The multiples of 855 are all integers evenly divisible by 855, that is all numbers such that the remainder of the division by 855 is zero. There are infinitely many multiples of 855. The smallest multiples of 855 are:

## 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 855). 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 29.240). 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 855

• Preceding numbers: …853, 854
• Following numbers: 856, 857

### Nearest numbers from 855

• Preceding prime number: 853
• Following prime number: 857
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