Conversion Functions Oracle PLSQL

Syntax: TO_CHAR( [,[FORMAT] [,NLS_PARAM]] )
SQL>
SQL> SELECT
  2     LENGTHB(NCHR(216))  national,
  3     LENGTHB(TO_CHAR(NCHR(216))) converted
  4  FROM dual;
  NATIONAL  CONVERTED
---------- ----------
         2          1