@Mohammad it is recommended that no more than 30 clients are connected per radio (so 30 for 2.4GHz and 30 for 5GHz) unless you are using VoIP when it is recommended that no more than 10 clients are connected to the radio with the VoIP clients, the other can still have 30 clients.
Having said that, I have seen 100 clients on a radio and as long as they are low demand (phones checking for email etc.) then the maximum used to be 128 per radio, though I seem to remember that this can be exceeded on either some new hardware or new software (sorry I cannot remember exactly which, as I would not recommend getting near that!