The show interface port-channel summary command shows the LAG number (VLT port channel 11 in this example), the mode, status, and ports used in the port channel.
Z9664-1# show interface port-channel summary
LAG Mode Status Uptime Ports
11 L2 up 00:04:43 Eth 1/1/11:1 (Up)
Eth 1/1/49:1 (Up)