IsNumber

Reports whether the value of a string is a number.

IsNumber ( string )

Argument	Description
string	A string whose value you want to test to determine whether it is a valid number

Boolean. Returns true if string is a valid number and false if it is not.

This expression returns true:

IsNumber("32.65")

This expression returns false:

IsNumber("A16")

This expression for a computed field returns “Not a valid age” if age does not contain a number:

If(IsNumber(age), age, "Not a valid age")

To pass this validation rule, Age_nbr must be a number:

IsNumber(Age_nbr) = true