A credit card number consists of a series of 16 digits. Cards starting with 4 are VISA cards, cards starting with 5 are MasterCard, JCB cards and American Express cards usually start with 3, and the most common China UnionPay card starts with 62.

The first six digits of the card number are formulated in accordance with the ISO/IEC7812 document, which can help cardholders and merchants identify the issuer of the bank card. Bank card numbers that comply with the ISO/IEC7812 standard are usually 16 digits and can be up to 19 digits long. The 7th to 15th digits of the credit card, that is, the bank account, are all defined by the bank itself. Each bank has different rules. Just understand that this is your own bank account.