A deduction by more than 60% is a robbery not taxation, imo. If lottery tickets are subject to sales tax then the winnings should be tax free
And I used to think the 25% my country imposes on lottery winnings was unfair!.
Still, ~$400 million is a huge amount of money so congratulation to the winner, whoever he is.
A deduction of 60% is a robbery and it is fair to keep the entire winnings, the only places i know that will allow you to keep all the winnings are places like UAE where the government allows you to keep all your winnings as there are government jackpots as well but the ticket charges are really high but if you are lucky you could keep all the amount you won.