You might have always assumed that the bevelled 16 digit number on a credit card is completely random and is unique to every assigned card out there so that its unique and randomly generated number is assigned to that specific card and can never be used by anyone else. But as it stands, there is a lot more to those numbers than just that.
The 16 digit number on a credit card, usually called the primary account number, can be categorised into 3 distinct groups of characters:
The first 6 digits aren't uniquely linked to you or your account but rather used to identify the issuer and its purpose such as airline companies, entertainment companies, private users, petroleum industry etc. As well as identifying whether it's a Visa or Mastercard etc.
The next group of 9 digits is used to identify the specific user account associated with that credit card.
Lastly, we have the final digit (the last digit on the card) which is also called the check digit. The Check digit is used with the help of the Luhn Algorithm to detect whether or not each other number on the card is legitimate and not fraudulent.
Take a look at the video below by the YouTube channel: Half As Interesting on How To Decode Credit Card Numbers...