The number of a VISA credit card is usually 16 digits, and the first 16 digit is BINNO. From the issuing bank. Bit 7 12: card serial number; Bit 13: represents the primary and secondary cards, 0 represents the primary card, and 1-9 represents the secondary card; Bit 14: represents the date when the card statement is issued; Number 15: indicates which card this card is. If your visa card is a replacement card, 1 will be added. 16 bits: it is the check code. In addition, as for the quantity, VISA itself does not make specific provisions, but is defined by each card-issuing bank. Therefore, different card-issuing banks have different definitions of the number 13.

ICBC card has 15 digits, 16 digits, and 18 digits, 19 digits! It depends on what kind of card you are. ICBC's general card number starts with 95588 or 6222. If it starts with the above two cards, the card number should be 19 digits. If it starts with 5309, 48 15 or 4580 digits, it is a credit card or debit card with 16 digits.