That's an extraordinary amount of money. A lot of the lists already given wouldn't even touch the sides.
I would spend the week as normal because I would be unable to believe it was real until it hit my actual (new, presumably Coutts) bank account. In the meantime, I would be making lists of what I want to spend it on whilst also trying to get my head around it.
The list would include a big helping hand to my whole extended family, including cousins I haven't seen forever, and everyone's children. All mortgages paid off. There isn't much money in the family at all so that alone would make a big difference to people.
Then I would buy lovely properties for my immediate family. If they want it, private school for my niece and nephew. Better homes, or home help for my parents, who are getting older. I would also set my parents and siblings up with pensions/invested money to make an income over time.
I would take them all out to a lovely hotel and get a private dining room, then tell them over dinner.
For me, I would buy a lovely house and better car. I would quietly resign from my current job, invest in career development and decide my next move in my own good time. I might take some time out to write. I would get the pets I would like to have. I would plan some lovely parties and holidays for family and friends. I would also sensibly invest in a personal pension / for income.
I've probably spent it now...!