The first 6 digits are the bank identifier of the issuer (bank) that issued the card (BIN card), which a particular payment system assigns to a specific bank for a specific type of card.
The first digit of the BIN number of the card indicates membership in the payment system:
- American Express – 3;
- JCB International - 3;
- VISA – 4;
- MasterCard – 5;
- China UnionPay - 6;
- Maestro - 3, 5 or 6;
- World - 2.
The numbers 7 through 15 are the identification number of the card and the card type (debit, credit or prepaid card), currency, region of issue.
The last 16 digit is the number by which the correctness of the card number is determined.