Look Inside $2 Billion Powerball Winner's $25 Million Hollywood Hills Mansion

The Powerball winner, turned instant billionaire, obviously has a lot to celebrate ... but wait until you see inside the home he purchased with just a fraction of his winnings.

The three-story $25.5M mega-mansion sits in the Hollywood Hills and has all the bells and whistles you'd imagine ... and even some you wouldn't!

For starters, the kitchen looks like something out of the future -- with glass doors that open to the outside and beautiful granite countertops. There's plenty of living space too, with 13,578 sq ft total.

There's also plenty available for entertaining the new billionaire and his guests -- with a movie theater, game room, wine cellar bar, gym and a sauna area that looks like it's straight out of a resort.

As we reported ... Edwin Castro, the winner of November's $2.04 billion Powerball prize, scooped up the huge Hollywood estate ... just one month after taking home his one-time payment of $997.6M before taxes.

Castro won't have any problem making room for any visitors either -- the place has a five-car showroom, in addition to a separate two-car garage and over seven gated off-street parking spots ... which is the equivalent of gold in the Hills.

Of course, the backyard is stacked with an infinity pool, full outdoor kitchen and a rooftop deck with breathtaking views.