new lenny conundrum now

Fifteen different farmers each had their own apple orchards. The first farmer had only one apple tree in his orchard, the second farmer had two trees in his orchard, and so on up to fifteen trees for the fifteenth farmer.


At harvest time, each farmer noticed something very peculiar: each tree in the same orchard produced the exact same number of apples. (Note that the number of apples per tree varied from orchard to orchard) And when all fifteen farmers got together to talk about it, they all realized that, if the farmer with eleven trees had given one apple to the farmer with seven trees, and the farmer with fourteen trees had given three apples each to the farmer with nine trees and the farmer with thirteen trees, they'd all end up with the exact same number of apples!

How many apples did all the farmers produce, in total?