@Gayathri Devi,
Can you try this query
insert into table tblename select * from (select from_unixtime(unix_timestamp('161223000001', 'yyMMddHHmmss')))b;
#2) If you have timestamp as '1506614501'
hive> select from_unixtime(unix_timestamp('1506614501', 'yyMMddHHmm'));
OK
2015-08-01 21:01:00
Time taken: 0.257 seconds, Fetched: 1 row(s)
Thanks,
Aditya