There is no way to judge the bank of CCB credit card by the card number.
His credit card bank is generally the same as the province where the landlord holds the card. Of course, in some cities, such as Shanghai, Beijing, Tianjin, Chongqing, Suzhou, Qingdao, Ningbo, Dalian and Shenzhen (CCB official website will list these branches), if the landlord applies for a card in these cities, it is the corresponding branch of these cities.
For example, if the landlord is from Shenzhen, then the card belongs to Shenzhen Branch, not Guangdong Branch.
If the landlord can't remember the situation clearly when handling the card, he can only call his home service hotline to confirm.