Filter integers and integer strings

FilterIntegersAndStrings.php

<?php

$numbers = array(
	12,
	1551,
	'21',
	'5115',
	'I am a string',
);

//set to loop over the numbers array. 
foreach( $numbers as $number ) {
	
	//check to see if the value is either an integer or a numeric string.
	if( is_numeric( $number ) ) {
		
		//filters integers
		if( is_int( $number) ) {
			
			echo $number . ' is an integer.' . '</br>'; 
			
		//filters numeric strings 		
		} elseif ( intval( $number ) ) {
			
			echo $number . ' is a numeric string, please convert to an integer.' . '</br>';
			
		}
	}
}
?>

****OUTPUT****
12 is an integer.
1551 is an integer.
21 is a string please convert to an integer.
5115 is a string please convert to an integer.
**************