Defer paying taxes on selling primary residence

[Shak Amir]

Hi all, A friend of mine is planning to sell a primary house he bought many years ago. He bought it for 400 and spent 100k on it and now it is appraising for 1.4 million. His total profit will be around 900k. I think first 500k of profit is exempt from tax, what can do for the next 400k. He wants to buy a 600k primary house and rest of money for investment property. Can he do 1031 exchange to defer taxes. Or if he just wants to pay the tax, would it be at long term capital gain rate of 20%?