If you ever want to check your overall investment statistics per planet, it's easy as lemon pie! Tap on your Menu, then Career, then on the Statistics icon in the top-left. From there, you can scroll down and check the following:
Cash on Hand: Your current cash amount on that respective planet.
Session Earnings: How much you've earned overall in that playing session (this will reset after resetting for Angel Investors).
Lifetime Planet Earnings: The total cash you've earned on the respective planet.
Total Resets: How many times you've reset the planet to gain Angel Investors.
Total Angel Investors: Your current amount of Angel Investors.
Angels Sacrificed: How many Angel Investors you've sacrificed for upgrades.
Unlocks Earned: Total number of unlocks earned.
One more thing; if you've completed a planet and opted out of reseting your stats, you can reset the planet through the Stats menu whenever you're ready to start your adventure over again!