ISEMPTY function
Cell-is-empty function. ISEMPTY(var) returns the logical value 1 (=TRUE) if the calculation of var does not result in a numeric or text value.
Examples
ISEMPTY(B2) returns 0 (=FALSE) if cell B2 contains a number or a string value, e.g. "SMITH".
ISEMPTY(25.6) returns 0