PHP's number_format() with  

PHP’s number_format() can’t take a   as a separator, which is bad when you want the separator to be whitespace inside HTML, since using a normal blank (a ” “) breaks the number when it happens to be laid out between to lines.

Svein Tjonndal has written the following little function which essentially does a number_format with   as the thousands separator:

function numberfix($number)
   $number = number_format($number,0,","," ");
   return str_replace(" ", " ", $number);