If you ever want to check your overall investment statistics per planet, it's easy as lemon pie! Tap on your Capitalist Profile Picture in the top left, then on the Statistics tab. 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!