|Divisors||1, 2, 4, 5, 8, 10, 16, 20, 40, 80|
The sum of Euler's totient function φ(x) over the first sixteen integers is 80.
- According to Exodus 7:7, Moses was 80 years old when he initially spoke to Pharaoh on behalf of his people. Today, 80 years of age is the upper age limit for cardinals to vote in papal elections.
- According to sayings from Islamic Prophet Muhammad, Prophet Abraham was circumcised when he was 80 years old.
Jerry Rice wore the number 80 for the majority of his NFL career. The number 80 is also the retired number of Seattle Seahawks wide receiver Steve Largent; when Rice was traded to the Seahawks, Largent gave the team permission to unretire his number so Rice could wear it.
In other fields
Eighty is also:
- used in the classic book title Around the World in Eighty Days
- the length of the Eighty Years' War or Dutch revolt (1568–1648)
- the standard TCP/IP port number for HTTP connections
- the 80A, 80B and 80C photographic filters correct for excessive redness under tungsten lighting
- The year AD 80, 80 BC, or 1980
- Eighty shilling ale
- I-80 is an interstate highway going from New York to San Francisco
- The older four-pin-base version of the 5Y3GT rectifier tube
- A common limit for the characters per line, in computing, derived from the number of columns in IBM cards
- American band Green Day has a song called "80"
- A fictional alien superhero named Ultraman 80
- The number of victories Manfred von Richthofen got when he was a German fighter pilot with the Imperial German Army Air Service (Luftstreitkräfte) during World War I. Richthofen is still the most successful flying ace of World War I.
- Bunkley, Nick (March 3, 2008), "Joseph Juran, 103, Pioneer in Quality Control, Dies", New York Times.
- What is 80/20 Rule, Pareto’s Law, Pareto Principle.
|Wikimedia Commons has media related to 80 (number).|
- wiktionary:eighty for 80 in other languages.