What are the first and the last 20 digits of: 7^7^7^7? Any help or hint would be appreciated. Thank you.

Guest Sep 10, 2019

#1**+1 **

first 20 digits: 73897156067403508131

last 20: 33408341373887572343

please correct me if i'm wrong :)

pinklemonade Sep 10, 2019