To be safe, get two Bitcoins.
lol i agree with this. in 20 years 2 bitcoin may be worth 2,000,000$ and to me a 2m retirement fund would last if you plan on retiring at 60 and living untill 75 or whatever. specially if you have another income coming in still from ssi or whatever it may be
safe side get 5
I do not think that the price per Bitcoin is going to be a million that is not happening. There are people with hundreds of Bitcoins so by your predictions that means that so many people will be a millionaire if they just have one Bitcoin,