620 US gallons in US customary cups
Result
The conversion result is: 620 US gallons is equivalent to 9920 US customary cups.[1]
Conversion formula
How to convert 620 US gallons to US customary cups?
We know (by definition) that: 1 usgallon ≈ 16 uscup.
We can set up a proportion to solve for the number of US customary cups.
1 usgallon / 620 usgallon ≈ 16 uscup / x uscup
Now, we cross multiply to solve for our unknown x:
x uscup ≈ (620 usgallon / 1 usgallon) * 16 uscup → x uscup ≈ 9920 uscup
Conclusion:
620 usgallon ≈ 9920 uscup

Conversion in the opposite direction
The inverse of the conversion factor is that 1 US customary cup is equal to 0.000100806451612903 times 620 US gallons.
It can also be expressed as: 620 US gallons is equal to 1 / 0.000100806451612903 US customary cups.
Approximation
An approximate numerical result would be: six hundred and twenty US gallons is about nine thousand, nine hundred and twenty US customary cups, or alternatively, a US customary cup is about zero times six hundred and twenty US gallons.
Footnotes
[1] The precision is 15 significant digits (fourteen digits to the right of the decimal point).
Results may contain small errors due to the use of floating point arithmetic.