There are a lot of method for find this information about oracle database is 32 bit or 64 bit, here is one of them, also here is method to find os version from database:
[oracle@oel6 ~]$ sqlplus / as sysdba
SQL*Plus: Release 11.2.0.3.0 Production on Fri Feb 8 12:31:24 2013
Copyright (c) 1982, 2011, Oracle. All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
With the Partitioning, Automatic Storage Management, OLAP, Data Mining
and Real Application Testing options
SQL> select length(addr)*4 || '-bits' Bits from v$process where rownum=1;
BITS
---------------------------------------------
64-bits
for operating system information (OS) version:
SQL> select dbms_utility.port_string from dual;
PORT_STRING
--------------------------
x86_64/Linux 2.4.xx
