I want to make a portable flash drive with Ubuntu Mate on it as backup and keep that flash drive in my backpack (which I take everywhere). I don't like to use other people's computers, so I'd rather have an own OS ready to use whenever needed. My intention is having the flash drive carry the actual system of Ubuntu Mate, not an installer.
Now I'm not entirely sure what to install, 64-bit or 32-bit.
My main reason for that is that I don't know if plugging in my flash drive (with 64-bit Ubuntu Mate) on a 32-bit hardware machine, I can actually boot and use it.
Is that possible or should I go with 32-bit for compatibility?
Editing because of "possible duplicate": I think my question is similar, though more specific. I'd find it weird if moderators would not consider this a question on it's own. I've also been searching for an answer to this, for over an hour, without finding one. That's why I'm asking it on here.