<?php
echo amIprime($num);
function amIprime($num,$i=1){
return (is_numeric($num))
? (($num<=20020)
? (($num%$i==0 && $i!=1 && $num!=2)
? "Not Prime Number"
: (($i<=$num/2)
? amIprime($num,++$i)
: "Prime Number"))
: "This isn't a number";
}
?>