преобразование числа в шестнадцатиричное

select to_char('16384', 'XXXXX') from dual
/ 
4000

CREATE OR REPLACE Function IntToHex(mInt varchar2 default '0') RETURN VARCHAR2 IS
-- select inttohex('16384') from dual
     mHex Varchar2(7);
BEGIN
  select ('#'||replace(to_char(mInt,'XXXXX'),' ','0')) into mHex from dual;
  return mHex;
END IntToHex;

CREATE OR REPLACE Function IntToHex(mInt varchar2 default '0') RETURN VARCHAR2 IS
-- select inttohex('16384') from dual
     mHex Varchar2(7);
BEGIN
  select ('#'||replace(to_char(mInt,'XXXXX'),' ','0')) into mHex from dual;
  return mHex;
END IntToHex;

SQL> set serveroutput on
SQL> declare
  2      mHex Varchar2(7);
  3  begin
  4      mHex := '#' || to_char(16384,'FM0XXXXX');
  5      dbms_output.put_line('mHex is "' || mHex || '"');
  6  end;
  7  /
mHex is "#004000"

PL/SQL procedure successfully completed.

SQL>