National Yellow Pig Day

National Yellow Pig Day Cartoon

National Yellow Pig Day on July 17 honors the unique attributes of the number 17 and its significance to mathematics.

If you don’t think the number 17 plays any role in our lives, consider these facts:

  • The number 17 is a premium number in the arena of prime numbers. Add the first four prime numbers together, and 17 is their sum.
  • The average school bus weighs 17 tons with passengers inside.
  • Each of the following words has 17 letters:
    • interdisciplinary
    • telecommunication
    • misinterpretation
    • commercialization
    • electrophotometer
  • The atomic number of chlorine is 17.
  • Pebble Beach has a specific road known as the 17 Mile Drive along the Monterey Peninsula in California. However, the exact length of the road is 16.78 miles.
  • The 17th Amendment of the U.S. Constitution gave the citizens of the United States the right to elect their senators by popular vote. Before the states ratified the amendment on April 8, 1913, each states’ legislatures would elect the senators to Congress.

Look for the not so random occurrence of the number 17.  Look!  Yellow pig!


Brush up on your calculus and round up your yellow pigs. Look for the number 17. It’s everywhere!  Post on social media using #NationalYellowPigDay.


Our research found National Pig Day originates sometime during the early 1960s. Two mathematicians by the name of Michael Spivak and David Kelly were analyzing the random properties of the number 17 and a mysterious yellow pig. It seems the process became excessive and professional. Kelly gave lectures and taught classes around Yellow Pig and Spivak made publications in several mathematics texts. While not based upon it, Spivak does subtly reference the number 17 and Yellow Pig.

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