Question: In 2009 D gave his son a gift of stock valued at $2,160,000, which produced a taxable gift of $2,147,000 and a gift tax, after application of the $345,800 applicable credit amount, of $507,030. D made no other lifetime transfers and was not married at his death. D died in 2016, leaving a gross estate of $7,600,000, with deductible expenses and claims of $900,000. D made an outright bequest in his will of $300,000 to a qualified charity and left the rest of his property to his son. Determine the estate tax payable at D's death.