There are generally two types of bank cards. One is debit card, also called bank savings card. This card can be used for deposit and withdrawal and transfer, but it cannot be overdrawn. This card number is generally 19, such as 19 for ICBC and Agricultural Bank, and 17 for China Merchants Bank, China Construction Bank and Bank of Communications.
The other is a credit card, usually called a credit card. Credit cards can be overdrawn by a certain amount for consumption, and the digits of credit cards are generally 16. So it depends on which bank card you are and what card you are.
Extended data:
Bank card number refers to the number code on the hard card issued by each bank, and the business number segment between commercial banks has unified regulations. The first six digits of the card number represent the identification code of the issuing bank, also called BIN number, and different BIN numbers represent different bank card organizations and card levels.
Once the bank card transfers money, the basic information, amount and transaction status of the customer will be transmitted to the central bank in time, and a large amount of information such as money laundering prevention and statistics will be summarized in the central bank database, which is the medium of unified financial management.
Bank cards are useless except for recording customer information and capital flow information. Magnetic, easy to degauss with mobile phone.
References:
Baidu encyclopedia-bank card number