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).
There are 193 states in the world â all recognized by the United Nations and members. Together comprise the ten smallest countries of this world so much that their surface area if put together is still smaller than Mexico City, which covers 1,499 square kilometers of urban area. Here, below are 10 of the worldâs smallest states, some of these has no armed forces at all. 1. Vatican City State.