Yes - $500,000 fast tracks you to a green card - it's called an EB-5 visa.
However, there are yearly limits on how many are issued - and for the past few years, 80% of them have gone predominantly to one place (not KSA).
BTW, the $500K has to be on deposit in a US-based bank, I believe, and may need to be invested / 'at risk'.
Regarding property, since you asked - you can own it here without being a citizen (or even a resident.) You could buy property here tomorrow, if you chose. Might not be able to get in here to *see* that property, but if you've got the money, we've got a deed.
If you are serious about gaining entry, check out
www.state.gov - our US State Dept website. There's a section there on immigration, etc.
As someone stated earlier - unless you're really wanting to buy your way in via EB-5, a student visa would probably be your quickest route. And there's no post-grad residency requirement - one can take their newly bestowed US degree(s) and go back to their homeland, or anywhere else they like, afterward. Many Chinese nationals do this, for example; others too (some are even beneficiaries of something called 'birth tourism', but that's another conversation.)
Personally, at your age, I'd look at Canada - and it only costs $135K (CAD) or so to 'buy your way in' there, the last time I looked. Outside of that, Canada uses a merit-based (points) system, so it can be harder to gain entry (it helps to be younger, bilingual, and in a labor segment deemed to be critical to the national interest.) Or pony up your $135K and get to the head of the line.
Canada's going to be a good place to live in the coming years, for a lot of reasons.
Sadly, I'm not entrepreneurial, and over 50 - so the only way I can get in, is as a tourist (6 mos max visit on tourist visa).