On: Prime numbers so memorable that people hunt for th...

[zellyn]

One of my pet hobbies is trying to figure out the least prime prime number and most prime composite numbers under 100.

My votes are 61 or 89 for least prime-seeming primes and 87 and --yep-- 57 for more prime-seeming composites.

[im3w1l → zellyn]

I'm gonna vote 91, since it has large divisors that can't be seen at a glance. 57 and 87 fall apart if you remember that 60 and 90 are divisible by 3.

[expensive_news → zellyn]

I really enjoy this “proof” that the most prime-seeming composite is 91

https://youtu.be/S75VTAGKQpk

[xigoi → zellyn]

I once wrote in a Math Olympiad solution that 87 is prime. Not my brightest moment.