How to find port opened by a process?

[root@server1 ~]# ps -eaf | grep  20927 
apache   20927  1740  0 03:32 ?        00:00:00 /usr/sbin/httpd


[root@server1 ~]# lsof -p 20927 -i -a
COMMAND   PID   USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
httpd   20927 apache    5u  IPv6  11430      0t0  TCP *:http (LISTEN)
httpd   20927 apache    7u  IPv6  11434      0t0  TCP *:https (LISTEN)