Double checked it with a handful of others code that's been posted online for this. Definitely 12, not even sure how I would go about proving it's the smallest one unless I was gonna brute force numbers up to ~500 digits (lol). Not sure what arXiv is, but tomorrow when I wake up I'll check it out and see what they think. Thanks guys

@SidharthGhoshal Just tried that out for fun lol, goes to 0 after 1 step as if you get a number with a zero in it anywhere, the process will always terminate on the next step. But also, no, I do not have proof this is the smallest such number, just a such number. As far as I look online, nobody has found any number with a persistence of 12, so I doubt this is the smallest one as well.

Yeah I've seen that post. Number I found has 500 digits ^. Still don't know how to send direct replies @SidharthGhoshal

Still no idea if this comment is notifying you as a reply, or just a standard comment, but I pushed enter trying to go to next line earlier, I meant to explain in my original reply, my bad. ^ Edited first comment.

Not sure if this reply button is replying to you or my post in general, but yeah sorry about that. Just don't know where else to ask. Multiplicative persistence as in, multiply every digit in a number by each other, how many steps to reach a single digit number. Highest persistence I can see found online is 11. So the code is just taking a number and multiplying the digits together until > 10. Pretty hard to believe there would be a bug in the code since it's so simple, but yeah. Sorry about not explaining.