The credit card of Bank of Communications has a 16-digit card number

The first to sixth digits are the credit card BIN code, and the first digit is the card organization code

Transportation Banks only have numbers starting with 4, 5, and 6

Of which 4 is a VISA card, 5 is a Master card, and 6 is a UnionPay single currency card

The 2-6 digits are allocated by the card organization Code for each bank