PL/SQL: function that will check if the NUMBER fields entered are valid numbers

-- A function that will check if the NUMBER fields entered are valid numbers
--- To Make sure that all the Number Fields are valid numbers
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FUNCTION MCIBE_ISNUMBER( p_string IN VARCHAR2) RETURN VARCHAR2 IS
l_number NUMBER;
BEGIN
l_number := to_number( NVL(TRIM(p_string),'-9999') );
IF ( CEIL(l_number) - (l_number) ) > 0 THEN
RETURN '2'; --- A number with decimal point
ELSIF l_number = 0 THEN
RETURN '1';
ELSE
RETURN '0'; ---A whole number
END IF;
EXCEPTION
WHEN OTHERS THEN
RETURN '1';
END MCIBE_ISNUMBER;