function rakam_ceil_f($rakam_p)
{
   $rakam = explode(',',$rakam_p);

   if(count($rakam) < 2)
   {
      $rakam_1    = preg_replace("#(\d\d)(\d)#u",'${1}0',$rakam[0]);
      $rakam_ceil = $rakam_1;

      return $rakam_ceil;
   }
   else if(count($rakam) == 2)
   {
      $rakam_1    = preg_replace("#(\d\d)(\d)#u",'${1}0',$rakam[0]);
      $rakam_2    = preg_replace("#(\d)(\d+)#u",'${1}00',$rakam[1]);
      $rakam_ceil = $rakam_1.',000';

      return $rakam_ceil;
   }
   else if(count($rakam) > 2)
   {
      $rakam_ceil = $rakam[0].','.preg_replace("#(\d)(\d+)#u",'${1}00',$rakam[1]);

      for($i = 2; $i < count($rakam); $i++)
      {
         $rakam_ceil .= ',000';
      }

      return $rakam_ceil;
   }
}

$rakam = "1,564,254";
echo $rakam.' > '.rakam_ceil_f($rakam);
echo "<br />";

$rakam = "651,566";
echo $rakam.' > '.rakam_ceil_f($rakam);
echo "<br />";

$rakam = "4,845,544";
echo $rakam.' > '.rakam_ceil_f($rakam);
echo "<br />";

$rakam = "54,845,544";
echo $rakam.' > '.rakam_ceil_f($rakam);
echo "<br />";

$rakam = "564,845,544";
echo $rakam.' > '.rakam_ceil_f($rakam);
echo "<br />";

$rakam = "564,845,544,445,44";
echo $rakam.' > '.rakam_ceil_f($rakam);
echo "<br />";

$rakam = "564";
echo $rakam.' > '.rakam_ceil_f($rakam);

Sonuçlar :

1,564,254 > 1,500,000
651,566 > 650,000
4,845,544 > 4,800,000
54,845,544 > 54,800,000
564,845,544 > 564,800,000
564,845,544,445,44 > 564,800,000,000,000
564 > 560