Is 851 a prime number? What are the divisors of 851?

## Parity of 851

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

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## Is 851 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 851 is about 29.172.

Thus, the square root of 851 is not an integer, and therefore 851 is not a square number.

## What is the square number of 851?

The square of a number (here 851) is the result of the product of this number (851) by itself (i.e., 851 × 851); the square of 851 is sometimes called "raising 851 to the power 2", or "851 squared".

The square of 851 is 724 201 because 851 × 851 = 8512 = 724 201.

As a consequence, 851 is the square root of 724 201.

## Number of digits of 851

851 is a number with 3 digits.

## What are the multiples of 851?

The multiples of 851 are all integers evenly divisible by 851, that is all numbers such that the remainder of the division by 851 is zero. There are infinitely many multiples of 851. The smallest multiples of 851 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 851). 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 29.172). 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 851

• Preceding numbers: …849, 850
• Following numbers: 852, 853

### Nearest numbers from 851

• Preceding prime number: 839
• Following prime number: 853
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