PHP: Nice human readable big numbers

gistfile1.txt

function bd_nice_number($n) {
        // first strip any formatting;
        $n = (0+str_replace(",","",$n));
       
        // is this a number?
        if(!is_numeric($n)) return false;
       
        // now filter it;
        if($n>1000000000000) return round(($n/1000000000000),1).' trillion';
        else if($n>1000000000) return round(($n/1000000000),1).' billion';
        else if($n>1000000) return round(($n/1000000),1).' million';
        else if($n>1000) return round(($n/1000),1).' thousand';
       
        return number_format($n);
    }
    
// Outputs:

// 247,704,360 -> 247.7 million
// 866,965,260,000 -> 867 billion