The first thing I would do is employ an attorney, and an accountant/financial advisor, this is before I cashed out. I would consider taking the annuity option because the stock market has been so screwed up lately. you could take the cash, and have 600,000,000 one day, and you could lose 50,000,000 overnight 300,000,000 in a month!!. If you invested in a good bond fund (no guarantee) with less risk, maybe 4% return you could expect to double your $$ in 18 years (4% into 72) so the annuity would be about the same.
With the cash, I would have the attorney set up a trust for all of my family and friends, and give them all an allowance (I hate to call it that) over there lifetimes, and they would be allowed to give the $$ to there heirs. So many lotto winners have declared bankruptcy, if you gave them all 1,000,000, they might be broke in a few months.
Then I would start a charitable foundation for my favorite charities, one or 2 of my children would be the administrator/s.
Then I would spend my life traveling, first to the Galapagos Islands, the Australia and Madagascar and the South Pole, I would also hire lobbiests to convince Japan and other nations to stop killing whales, even if I had to pay them. I would fund "no kill" shelters around the country as well.
I could go on and on........