1. Bank outlet inquiry: You can directly go to any business outlet of the bank to which the bank card belongs, consult the staff and inquire about your bank card joint number.
2. Bank customer service hotline: Call the official customer service telephone number of the bank, such as the Postal Savings Bank service hotline 95580, and switch to manual service according to the voice prompt. After providing personal information verification, customer service can help check the contact number.
3. Online inquiry: log in to the bank in official website or use the bank's mobile phone client. If you have the relevant query function, you can log in to your personal account and query the joint bank number. Or visit some third-party national bank joint line number inquiry websites and enter relevant information such as bank name, province and city. Used for searching and querying.
4. Check the back of the bank card: the joint bank number and UnionPay number are not the same concept. The UnionPay number is printed on the bank card, usually with 16 digits beginning with "62", while the inter-bank number is used to distinguish the bank branches and may not be directly displayed on the bank card.