So, I believe what Andy has said is correct in the math department. However, there are other items to think of when your trying to live off your Dividends and not your stock growth.
Such as in that 6% sustainable. What happens if they cut the dividend, Do you have a plan to recapture that income somewhere? etc. etc..
I HIGHLY recommend you take a close look at the DGI strategy if you want to live off of dividends. This IS a Stock picking strategy and is NOT for everyone, but it does work. I would check out
seekingalpha.com, and specifically look for articles by
David Van Knapp to get started. He is considered to be a very good resource for that. As well as seeking alpha in general.
If however, your looking at just using ETF's (Which I would also HIGHLY recommend, as it's just that much easier) consider that many sustainable ETF's play out around 2% on average. Which as an example, if you want to live on say 40k a year, your would need roughly 2 million invested (2Million * .02). Probably a little more then that actually, as the dividends do fluctuate with ETFs. Something i have noticed is that Dividends from these sources may not keep up with the rising cost of inflation. But should not, from what I have seen, be very far behind if at all.
You should also still consider what to do should your income fall short in a single month, (ie have a back up plan, like bonds or House rentals) but again, this works and I am aware of people who do live off income from dividends from etfs.
Before someone else says it. Yes there are tax consequences depending on the account everything is in. Ususally more with ETF's then with stocks (only talking on a dividend level), but it is something you need to be aware of and understand.
Finally, if you decided to use Dividends, don't go all googly eyed for large yields as they could be potential traps for your money. Especially when reality catches up with the stock/etf in question. Your reit may or may not fall into this category, I always find it hard to tell with those, but I have not done as much research in valuing those stocks.
From my personal view, I actually prefer to live off Dividends, and other income as it ensures I don't have to sell anything. Such plans could theoretically last forever, but I am sure someone has a different view on that. (Which is fine.)