Will restoring WhatsApp chats also restore my WhatsApp number
You should be able to restore your account using titanium backup if you have app+data backup of whatsapp taken using titanium backup. 

However, there can be cases of app crash, if the backup is corrupted, android version of your device upgraded/changed.
Also there can be a scenario in recent/latest version of whatsapp where it would detect this dirty restore and ask you to authenticate the number again. If this happens try using a bit older version of whatsapp(you can download it here) as I recall I was able restore whatsapp account using titanium backup a couple of years back.