In an empty cell, type 1 (this will be the multiplication factor used below, using 1 will not change the cell values)
Right click the cell, select copy, then , after selecting te column, from the paste special menu, choose operation Multiply--> ok. Press Esc from keyboard to exit CutCopyMode. All column will be reformated to General format, which means that the numbers are alligned to the right side of cell, and text is alligned on the left side of the cell. At this moment, the numbers from that column are recognised as numbers, not text, and can be used in another calculations. Anyway, does not matter if you need to use those numbers, this will remove also the information error.