Seems that the way to really kill this game is not to prestige at all. I just kept the game running for about 12 hours and maxed out everything without selling the shop. That got me a prestige bonus of over x1500. After that the game took about a minute to finish.
I will leave the game going now, earning a billion every 3.5 seconds. I want to see if the money goes to minus when it hits 2.14 trillion.