Investing is the best way to go about utilizing 21+ BTC. only to increase riches further.
thats true, ivesting into some kind of a new crypto with huge potential might be the thing you want to do in order to make money out of the money you already have
That is just a mere prediction that we are telling a crypto coin that has a good potential but it was not tested already, if you are talking to some altcoins, I would not trust my investment for a long period of time, you can only choose some high volume alts but most likely it is just a pump and dump game because only bitcoin is legit.
You need to choose some coins with high volume and invest in all of them, as those coins will not disappear easily and if you take decision at right them then you can make huge profits.