!!! Overview[1]
[{$pagename}]s or [Payment Card] numbers are found on [Payment Cards], which includes [Credit Cards] or and [Debit Cards], [Payment Tokens] as well as [Stored-value card]s, [Gift Card]s, [Loyalty Card]s and other similar cards. 

[{$pagename}] have a certain level of internal structure and share a common numbering scheme. [{$pagename}] are allocated in accordance with [ISO/IEC 7812|ISO 7812] and are most commonly 16 digits in length, and can be up to 19 digits. 

The [{$pagename}] format is:
* First digit - The [Major Industry Identifier] ([MII]) and is defined as:
* [Issuer Identification Number] - The first 6 digits of your credit card number (including the initial [MII] digit) is the [Issuer Identification Number] ([IIN]). 
* Account Number - Digits 7 to (n - 1) of your [{$pagename}] is the individual account identifier.
* a single check digit calculated using the Luhn algorithm.[2]

[{Image src='Bank Card Number/creditcard-number.jpg' caption='Credit Card' align=left width=640 height=480 style='font-size: 120%}]. 

!! Account Number
Digits 7 to (n - 1) of your credit card number are your individual account identifier. The maximum length of a credit card number is 19 digits. Since the initial 6 digits of a credit card number are the issuer identifier, and the final digit is the check digit, this means that the maximum length of the account number field is 19 - 7, or 12 digits. Each issuer therefore has a trillion (10 raised to the 12th power, or 1,000,000,000,000) possible account numbers.

If we consider the large number of potential customers and usurious interest rates charged by issuers, there is obviously a lot of money to be made in the credit card industry. In more civilized ages, people believed that usury was a grievous offense contrary to nature or a mortal sin, not an acceptable business practice (Aristotle, Politics 1.10; St. Thomas Aquinas, De Malo 13.4; Dante, Inferno 11.94-111; etc.).

Internally, the [Card Issuer] also would know individual account identifier has an association to:
* the customer
* And designated bank accounts (For Debit Cards)
* In the case of stored-value type cards, there may NOT be association with a particular customer.

!! Check Digit
The final digit of the [{$pagename}] is a check digit, akin to a checksum. Most [{$pagename}]s use the [Luhn Algorithm] for validation.

!! More Information
There might be more information for this subject on one of the following:
[{ReferringPagesPlugin before='*' after='\n' }]
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* [#1] - [Bank Card Number|Wikipedia:Bank_card_number|target='_blank'] - based on 2015-02-13
* [#2] - [Anatomy of Credit Card Numbers|http://mahercreditcard.blogspot.com//|target='_blank'] - based on information obtained 2016-01-15- 
* [#3] - [Anatomy of a credit card number and the utility of the BIN|http://www.dirigodev.com/blog/ecommerce/anatomy-of-a-credit-card-number/|target='_blank'] - based on information obtained 2016-01-15-