<?php if ($_SERVER["REQUEST_METHOD"] == "POST") { $num = intval($_POST["number"]); $isPrime = $num > 1 && !array_filter(range(2, sqrt($num)), fn($i) => $num % $i == 0); echo "$num is " . ($isPrime ? "a Prime number." : "not a Prime number."); } ?> <!DOCTYPE html> <html> <body> <form method="post"> Enter a number: <input type="number" name="number" required> <input type="submit" value="Check"> </form> </body> </html>