When Fermat said "All Fermat numbers are prime!" Euler basically said "Hold my quill pen" and factored 4,294,967,297 into 641 × 6,700,417... by hand . 🤯 Fermat numbers (2 2 n + 1) were thought to be prime for all values, but Euler crushed that dream with pure mathematical wizardry. He didn't need a calculator, supercomputer, or even electricity—just his brain and possibly an unhealthy obsession with large numbers. Meanwhile, I struggle to calculate a 15% tip without my phone. This is why mathematicians are the original flex masters of history!