Is 865 a prime number? What are the divisors of 865?

## Parity of 865

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

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## Is 865 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 865 is about 29.411.

Thus, the square root of 865 is not an integer, and therefore 865 is not a square number.

## What is the square number of 865?

The square of a number (here 865) is the result of the product of this number (865) by itself (i.e., 865 × 865); the square of 865 is sometimes called "raising 865 to the power 2", or "865 squared".

The square of 865 is 748 225 because 865 × 865 = 8652 = 748 225.

As a consequence, 865 is the square root of 748 225.

## Number of digits of 865

865 is a number with 3 digits.

## What are the multiples of 865?

The multiples of 865 are all integers evenly divisible by 865, that is all numbers such that the remainder of the division by 865 is zero. There are infinitely many multiples of 865. The smallest multiples of 865 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 865). 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 29.411). 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 865

• Preceding numbers: …863, 864
• Following numbers: 866, 867

### Nearest numbers from 865

• Preceding prime number: 863
• Following prime number: 877
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