The structure of bank card numbers varies depending on factors such as the type of card and the bank. Here are some common examples of bank card number structures: ### Debit Card 1. **ICBC Debit Card** - Generally 19 digits. For example: 6222021001000000001 - The first 6 digits "622202" are the BIN (Bank Identification Number) of ICBC Peony Money Link Card, which identifies the card organization, card type and other information. - The 7th to 18th digits "10010000000" are the serial numbers assigned to the card by the issuing bank, which are used to uniquely identify the card in the bank system. - The last digit "1" is the check digit, which is calculated by a specific algorithm and is used to verify the legitimacy of the card number. 2. **Bank of China Debit Card** - 19-digit card number. For example: 6217850100000000001 - The first 6 digits "621785" are the BIN of the Bank of China Great Wall Electronic Debit Card. - The middle 12 digits are the bank's internal serial number. - The last digit is the check digit. ### Credit Card 1. **China Construction Bank Credit Card** - Generally 16 digits. For example: 4367480000000000 - The first 6 digits "436748" are the BIN of the China Construction Bank Dragon Card Credit Card, where "4" indicates that this is a card of the VISA card organization. - The 7th to 15th digits are the serial number assigned internally by the issuing bank. - The last digit is the check digit. 2. **China Merchants Bank Credit Card** - 16-digit card number. For example: 4392250000000000 - The first 6 digits "439225" are the BIN of the China Merchants Bank Credit Card, which is also the logo of the VISA card organization. - The middle 9 digits are the bank's internal serial number. - The last digit is the check digit. The bank card number structure of different banks generally follows similar rules, but the specific details vary. This information is mainly used by the bank system to identify bank cards, process transactions, and control risks.