Find out given number even or odd without using mod operator ?

<?

$a = 47;

$b = $a/2;

if(!strpos($b,'.'))

{

            echo 'even';

}else

{

            echo 'odd';

}

?>

(or)

<?

$num = 13;

if($num&1){echo 'odd';}else{echo 'even';}

?>