The first six digits of a credit card number are called BIN, which can be used to determine which bank it belongs to, but a bank will correspond to the first of several six digits.

In addition, the first card number of a credit card is 4, and 5 is Master. 622 126~622925 is a unionpay standard card. 6 starts with China UnionPay single currency card (or American discover), the credit card number 4 starts with the international brand VISA credit card (the world's first credit card organization), 5 starts with the international brand MASTERCARD, and 3 starts with Japan JCB and American Express.