if number of items isn't divisiable by 3 php code example

Example: is number divisible by 3 php

if($number % 15 == 0)  {
    echo "BY3 AND 5";
} elseif ($number % 5 == 0) {
    echo "BY5";
} elseif ($number % 3 == 0) {
    echo "BY3";
}