What's special about 196?

Alex Bellos discusses how the Incans used knots in string (Quipu) to record numbers.Check out Brilliant (get 20% off their premium service): https://brillian...

Free audio book offer: http://www.audible.com/numberphile

Dr James Grime delves into the largely unresolved world of Lychrel Numbers?

James Grime: https://twitter.com/jamesgrime

For audio books by Numberphile stars, go to Audible and search these names; Hannah Fry, Alex Bellos, Simon Singh, Edward Frenkel --- http://www.audible.com/numberphile

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Cheryl's Birthday: https://youtu.be/emiMj8cCL5E