How to get exact SCN no in database

SELECT TO_CHAR(CURRENT_SCN) FROM V$DATABASE;

or:

SQL> column current_scn format 99999999999;
SQL> select current_scn from v$database;

 CURRENT_SCN
------------
     2981094

or:

SQL> select dbms_flashback.get_system_change_number current_scn from dual;