Big town is 5.121 times larger than Small town.
Explanation:
Step 1:
In order to determine how much larger Big town's population is to Small town's population is, we need to convert the exponentials into actual numbers.
Small town's population

Big town's population

Step 2:
In order to determine how much larger Big town's population is to Small town's population is, we divide Big town's population by Small town's population.

So Big town is 5.121 times larger than Small town.