open file count

Hi,
we have 3 nodes RAC. node 1 was the primary node application service was running. node 1 experienced kernel panic
and application service failed over to node 2 automatically. After failing over we noticed we couldn't login as oracle user to node2

when oracle user was blocked from logging into server, the
lsof |grep -i oracle |wc -l  ->  open file count
was hovering above  800000

openfiles parameter
ulimit -Hn ->
[root@camcrac-ora-prod-cr-01 ~]# ulimit -Hn
65536
[root@camcrac-ora-prod-cr-01 ~]#

[root@camcrac-ora-prod-cr-01 ~]# ulimit -Sn
65536

Hope open files is set to recommended value. should we increase it further.
What is oracle recommended setting for this kernel parameter.
Thanks.