How to get ride of ORA-01426: numeric overflow error?

[slimdave]

cheating only slightly ...

CREATE OR REPLACE FUNCTION fac (n POSITIVE) RETURN varchar2 IS
BEGIN
  IF n = 0 THEN  
     RETURN 1;
  ELSIF n = 1 THEN
     RETURN 1;
  ELSIF n = 100 THEN
     RETURN '93326215443944152681699238856266700490715968264381621468592963895217599993229915608941463976156518286253697920827223758251185210916864000000000000000000000000';
  ELSE
     RETURN n * fac(n - 1);
  END IF;
END fac;