Is 428 a prime number? What are the divisors of 428?

## Parity of 428

428 is an even number, because it is evenly divisible by 2: 428 / 2 = 214.

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## Is 428 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 428 is about 20.688.

Thus, the square root of 428 is not an integer, and therefore 428 is not a square number.

## What is the square number of 428?

The square of a number (here 428) is the result of the product of this number (428) by itself (i.e., 428 × 428); the square of 428 is sometimes called "raising 428 to the power 2", or "428 squared".

The square of 428 is 183 184 because 428 × 428 = 4282 = 183 184.

As a consequence, 428 is the square root of 183 184.

## Number of digits of 428

428 is a number with 3 digits.

## What are the multiples of 428?

The multiples of 428 are all integers evenly divisible by 428, that is all numbers such that the remainder of the division by 428 is zero. There are infinitely many multiples of 428. The smallest multiples of 428 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 428). 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 20.688). 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 428

• Preceding numbers: …426, 427
• Following numbers: 429, 430

### Nearest numbers from 428

• Preceding prime number: 421
• Following prime number: 431
Find out whether some integer is a prime number