The maximum length of the number of a credit card can be 19 digits, and the length of the account field can maximum be 12 digits. Each issuer can have a trillion possible numbers of an account. The final digit on a credit card number is a check one, similar to a checksum. It confirms the initial digits of the number and prevents the attempts to invent card numbers.
Longest lasting empire in history. The Roman Empire is considered to have been the most enduring in history. The formal start date of the empire remains the subject of debate, but most historians agree that the clock began ticking in 27 BC, when the Roman politician Octavian overthrew the Roman Republic to become Emperor Augustus.
The Kangxi Emperor's reign of 61 years makes him the longest-reigning emperor in Chinese history (although his grandson, the Qianlong Emperor, had the longest period of de facto power) and one of the longest-reigning rulers in the world.