Untouchable Numbers

A continuation of our video about 276 and Aliquot Sequences with Ben Sparks.

See the first part at https://youtu.be/OtYKDzXwDEE

Ben Sparks: https://www.bensparks.co.uk

More Ben Sparks on Numberphile: http://bit.ly/Sparks_Playlist

Perfect Numbers on Numberphile: https://www.youtube.com/playlist?list=PLt5AfwLFPxWJILwhaYs0Cz76-XK4cu3WC

Amicable Numbers: https://youtu.be/fUSZBVYZdKY