17504...79167 (20562-digits)

This number is a prime.

The largest known Mills' prime: ((((((2521008887^3+80)^3+12)^3+450)^3+894)^3+3636)^3+70756)^3+97220. Proven by Morain with ECPP in 2006, this prime surpassed the previous general prime record by over 5000 digits. [Caldwell]