The first six digits of the card number, inclusive of the MII, are called the IIN (Issuer Identification Number) or BIN (Bank Identification Number).
In this case, the MII of 5 indicates that this is a Mastercard card. The first digit of the card is known as the MII digit, and indicates the credit card's scheme. While credit card number may seem like a random string of digits, they actually contain a large amount of valuable data about the card that can be used for validation and verification purposes. Anatomy of a Bank Of America Mastercard Credit Card Number
