I found this error in the NY Times in an informative article about an app that helps you with flights (Skyscanner).
“You can filter this list in a number of ways to find the flight with the best price, the least amount of interim stops, and so on.” (Bold added by me.)
Here’s the rule: if you can count something, use “number.” If what you’re writing about is uncountable (e.g., milk, luggage, equipment), use “amount.”
Because you can count interim stops, the sentence should have read, “…the fewest/least number of interim stops.”
I shall stop now.