Factors of Mersenne Number M67/Historical Note

Historical Note on Factors of Mersenne Number $M_{67}$
The Factors of Mersenne Number $M_{67}$ were demonstrated by in a famously dramatic presentation On The Factorization of Large Numbers to a meeting of the American Mathematical Society in $1903$.

When called to give his lecture, he walked to the blackboard, and worked out the calculation, longhand, of $2^{67}$. Then he carefully subtracted $1$.

Moving to another area of the board, he then multiplied out $193, 707, 721 \times 761, 838, 257, 287$.

The numbers matched.

returned to his seat to thunderous applause, having delivered the only lecture in history in which not a word was spoken.

When asked how long it had taken him to find these factors, he reportedly replied: "three years of Sundays."