Returns FALSE. As FALSE()FALSE() always returns FALSE, there is little reason to use this function—it is mainly provided for compatibility with spreadsheets.
FORMATNUMBER(1234.56789, 2, 2, FALSE())FORMATNUMBER(1234,56789; 2; 2; FALSE())
Returns "1,234.57", which is the number 1234.56789 formatted as a text string with two decimal places and thousands separator. (The exact way a number is formatted as a text string varies with the language settings of the app.)