Using the Excel ISNUMBER Function

Summary
The Excel ISNUMBER function will return TRUE when a cell contains a number, and FALSE for any other values. The function is useful when determining if a cell contains a number or if the output of a formula is a numeric value.Syntax
=ISNUMBER (Value)Syntax Breakdown
ValueRequired. A value that will be tested to determine if it is a numeric value or not. Typically supplied as a cell address.
Usage Notes
ISNUMBER checks if a value is a number and returns TRUE if it is, and FALSE if it is not.The ISNUMBER function will return TRUE for dates and times since they are numbers. A number entered as text will return FALSE.