If anyone were to answer this question without you asking a bunch of questions first is doing you a great disservice.
Here are some factors:
1- how old are you? 2- what are your current debt situation? 3- what are your current investments? 4- what is your current income? 5- what is your current liabilities? 6- when do you plan to use this money? 7- is the 800k in some sort of inherited retirement plan like a ira or roth ira? 8- what is your current marginal tax bracket?
Etc, etc...
You'd be surprised how big of a mistake you can make here by doing the wrong thing.