You can use =text(date,"mmmm") to display it as a date. This is different is different to having the date and formatting the cell as "mmmm" as using text(...) makes it text (oddly enough), whereas formatting the cell means that the contents of the cell are still a number, but are displayed differently. This does make a difference in some situations - if there isn't enough room in a cell to display the value it will flow over to the next cell when displayed as text, but it will display as #### when it's a number.