string number_format (float number, int decimals, string dec_point, string thousands_sep)
Number_format() returns a formatted version of number. This function accepts either one, two or four parameters (not three):
If only one parameter is given, Number will be formatted without decimals, but with a comma (",") between every group of thousands.
If two parameters are given, number will be formatted with decimals decimals with a dot (".") in front, and a comma (",") between every group of thousands.
If all four parameters are given, number will be formatted with decimals decimals, dec_point instead of a dot (".") before the decimals and thousands_sep instead of a comma (",") between every group of thousands.