Write a php program to check wether a number is prime or not

Write a php program to check wether a number is prime or not 

<?php 

// PHP code to check wether a number is prime or Not

function primeCheck($number)

{ 

    if ($number == 1) 

    return 0; 

    for ($i = 2; $i <= $number/2; $i++)

{ 

        if ($number % $i == 0) 

            return 0; 

    } 

    return 1; 

} 

  

$number = 31; 

$flag = primeCheck($number); 

if ($flag == 1) 

    echo "Prime number"; 

else

    echo "Not Prime number"

?>