Organize and order prime numbers

i want to organize in some order , i have looked everywhere but not find . I don't know how to start i just have code of how to get prime numbers .

$n = $_POST['prime'];
$ct = 0;
$num = 2;
while ($ct < $n) {
    $dCt = 0;
    for ($i = 2; $i <= $num; $i++) {
        if (($num % $i) == 0) {
            $dCt++;
        }
    }
    if ($dCt == 1) {
        echo "<div class='dd'>".$num ."</div><br />";
        $ct++;
    }
    $num++;
}

I'm getting the numbers like that:

    2
    3
    5
    7
    11
    13
    17
    ....

What i want is like that

       2     3      5       7      
  11         13             17    19
             23                   29
  31                        37 

As you can see they are ordered the numbers which have same last number under each other and same ten numbers in same line. Looks like a table