I skeeted this and then read the more recent replies and some "just add the digits" people did show up.
Listen, before you stop and do that, I have noticed that it's 30 + 21 and thereby factored it to 3 and 17.
But the vibes are what they are. It should clearly be prime.
People were like "The digits add up to 6, it's clearly divisible by 3" and yes, that's true, but counterpoint:
Just look at it. Look at it, and tell me if you've ever seen a primer-looking number.
511 has very much the same vibes, and disappoints just as much in the "is it a prime" sense.
(Sure, it looks a little different if your brain has been poisoned by decades of base 2 or 8 or 16, but it gives off the same vibes in base 10)
