Concept:Express all numbers as products of primes and simplify exponents.Explanation:Step 1: Prime factorise each base:6=2×3, 35=5×7, 15=3×5, 14=2×7, 21=3×7.Step 2: Write the expression in prime factors:Numerator: 212×312×528×728×316×516=212×328×544×728.Denominator: 212×712×311×711=212×311×723.Step 3: Cancel common factors:212 cancels, 328/311=317, 728/723=75, 544 remains.Step 4: The simplified expression is 317×544×75.Step 5: Total prime factors = sum of exponents: 17+44+5=66.Answer:66