declare 
a integer:=&a;
c integer:=0;
i integer;
begin
   
   for i in 1 .. a-1
   loop
      if (mod(a,i)=0) then
         c:=c+i;
     end if;
    end loop;
  if c=a 
then 
   dbms_output.put_line('Perfect number');
else
  dbms_output.put_line('Not Perfect number');
end if;
end;
/