A Truely Large Prime
(Another of the Prime Pages' resources)
The Largest Known Primes Icon
 
New record prime: 274,207,281-1 with 22,338,618 digits by Cooper, Woltman, Kurowski, Blosser & GIMPS (7 Jan 2016).
Eve, the now ubiquitous eaves-dropper, first considered cryptology when her Dad showed her a very large prime.  Curiously it was also the smallest prime.
a big 2 is a big
prime
Image by Matthew Harvey © 2003