A Dog Ate My Homework

Leonhard’s math teacher loves prime numbers. As homework, the teacher gave Leonhard a number nnn, told him to do extensive research and find out whether the number was prime or not. Here, nnn is a natural number with no more than 121212 digits and no leading zeroes. Returning home from school, Leonhard left the homework at his reading table and went out to play with his friends. After coming back, he found out that his worst nightmare has become a reality. You guessed it right, his dog tore the homework into pieces.

This is a companion discussion topic for the original entry at https://toph.co/p/a-dog-ate-my-homework