# PHP – Prime Number Program | PHP Tutorial

Prime number program in PHP. We would love to share with you how to check whether a given number is prime or not.

In this tutorial, we will create a PHP function to check a given number is prime or not. And we will create a new PHP program with PHP form, that also checks a number is prime or not

## What is Prime Number?

Answer: A number that is only divisible by 1 and itself is called a prime number. The first few prime numbers are 2, 3, 5, 7, 11, 13, 17, 19, 23 and 29.

### prime number program in PHP

We will create a program in PHP that can check whether a given number is prime or not.

```<?php
function IsPrimeOrNot(\$n)
{
for(\$i=2; \$i<\$n; \$i++)
{
if(\$n % \$i ==0)
{
return 0;
}
}
return 1;
}
// Pass The Number For check it is prime or not
\$a = IsPrimeOrNot(5);
if (\$a==0)
echo 'This is not a Prime Number.....'."\n";
else
echo 'This is a Prime Number..'."\n";
?>
```

### Prime Number using Form in PHP

Here we will create PHP program with PHP Forms for how to check a whether a given number is prime or not.

```<html>
<title>Prime Number using Form in PHP</title>
<body>
<form action="<?php echo htmlspecialchars(\$_SERVER["PHP_SELF"]); ?>" method="post">
Enter a Number: <input type="text" name="input"><br><br>
<input type="submit" name="submit" value="Submit">
</form>
<?php
if(\$_POST)
{
\$input=\$_POST['input'];
for (\$i = 2; \$i <= \$input-1; \$i++) {
if (\$input % \$i == 0) {
\$value= True;
}
}
if (isset(\$value) &amp;&amp; \$value) {
echo 'The Number '. \$input . ' is not prime';
}  else {
echo 'The Number '. \$input . ' is prime';
}
}
?>
</body>
</html>
``` 