[danohu]

How about the most silent lecture?

"Cole’s lecture was different. He did not speak a single word. He simply went to the board, and began to calculate. On one side of the board, he calculated 267 – 1 = 147,573,952,589,676,412,927 by hand. Then he went to the other side of the board and worked out the product of 193,707,721 and 761,838,257,287, the factors of 147,573,952,589,676,412,927. After spending the silent hour working out the calculations, Cole simply turned around and went back to his seat, completely silent! The audience erupted into a standing ovation."

https://musingsonmath.com/2012/10/31/one-long-multiplication...

[jacquesm]

> 267 – 1 = 147,573,952,589,676,412,927 by hand

I think I spotted an error there.

[smichel17]

It should be 2^67 - 1.

[jacquesm]

That was the error.

[albedoa]

I erupted into a standing ovation before Cole even went to the other side of the board.

[slazaro]

> 2047 is a composite number with factors 23 and 87.

This is another error (though this one is actually in the article). The factors are 23 and 89.