Is 521 a prime number? What are the divisors of 521?

## Parity of 521

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

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## Is 521 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 521 is about 22.825.

Thus, the square root of 521 is not an integer, and therefore 521 is not a square number.

Anyway, 521 is a prime number, and a prime number cannot be a perfect square.

## What is the square number of 521?

The square of a number (here 521) is the result of the product of this number (521) by itself (i.e., 521 × 521); the square of 521 is sometimes called "raising 521 to the power 2", or "521 squared".

The square of 521 is 271 441 because 521 × 521 = 5212 = 271 441.

As a consequence, 521 is the square root of 271 441.

## Number of digits of 521

521 is a number with 3 digits.

## What are the multiples of 521?

The multiples of 521 are all integers evenly divisible by 521, that is all numbers such that the remainder of the division by 521 is zero. There are infinitely many multiples of 521. The smallest multiples of 521 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 521). 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 22.825). 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 521

• Preceding numbers: …519, 520
• Following numbers: 522, 523

### Nearest numbers from 521

• Preceding prime number: 509
• Following prime number: 523
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