Question 612318
Note that 91 = 7*13.


Intuitively there will be fewer multiples of 13 in the set {3,6,...,231}. The multiples of 13 in the set that are less than 231 are 3*13, 6*13, ..., 15*13, five multiples of 13.


You can find the multiples of 7 but there are definitely more than five of them.


Therefore the greatest power of 91 that divides 3*6*...*231 is 91^5.