Following the third, fourth, or fifth digit, every number up through 15 is the account number while that final number, 16, is the check digit. All Discover cards start with the number six and are 16 digits in length, while petroleum cards start with the number seven and airline cards start with the number one.
Vatican City. Vatican City â 0.2 square miles â The worldâs smallest state, the Vatican has a population of 770, none of whom are permanent residents. The tiny country which surrounds St. Peterâs Basilica is the spiritual center for the worldâs Roman Catholics (over 1 billion strong).
Back in 1980, Qatar was a country of just 0.2 million people, making it one of the smallest in the world, and in terms of residents, 1/37th of what London is today. But things have rapidly changed, largely because of an explosion in immigration. Here are some of the numbers that show what happened.