What do the numbers on the credit card...!

Have you ever wondered how companies that issue credit cards find the numbers they put on the cards?
Credit card companies have agreed to a set of rules. This is what the numbers mean.



 The first digit is the Major Industry Identifier (main identity of the industry). Identifies the category of the entity that issued the card.
1 and 2 airlines
are 3 trips and fun
4 and 5 are banks and financial institutions
are 6 commercial banks and
7 are oil companies
are telecommunications 8
9 is a national award
The first six digits indicate the issuer of the credit card Issuer Identification Number (INN). Identify the institution issuing the card.
Visa: 4xxxxx
Mastercard: 51xxxx - 55xxxx
Discover: 6011xx, 644xxx, 65xxxx
Amex: 34xxxx, 37xxxx
The cards can be identified by the number of IIN. A card that begins 376211 is an American Express Gold of Singapore Airlines Krisflyer. To 529962 means it is a prepaid MasterCard's Much-Music.
The 7th and the following digits without the latter's personal account.This creates a total of one trillion possible combinations.
The last digit is the digit verification. Used to verify the authenticity of the card with the algorithm Luhn.