Check if a cell value is a number and convert to string

The ISNUMBER() function will tell if a cell is a number. ISTEXT() can tell if a cell is text (including numbers stored as text). The TEXT() function can convert a number to a text string in a specified number format.

IS... functions: https://support.microsoft.com/en-us/...1-f2d869135665
TEXT function: https://support.microsoft.com/en-us/...8-93d29371225c
Number format codes: https://support.microsoft.com/en-us/...7-9c9354dd99f5