Hi!

Today I was surfing Wikipedia and came across this article — Palindromic prime

This article says that the largest known palindromic prime is $$$10^{474500}$$$ + $$$999 * 10^{237249} + 1$$$.

Well it is easy to see that this number is palindrome, but... why is it prime?

I don't find any proof, and I am really curios — how to proof that this number is prime, when number is quite big?