A scientist is culturing a strain of Escherichia coli in a liquid nutrient broth to study the growth-inhibiting effects of a new antibiotic.
Initially, a single bacterium is introduced into the broth. Under optimal conditions, the bacteria divide by binary fission, and their number doubles every 151515 minutes.
Assuming no cell death during this exponential growth phase, calculate the number of bacteria in the culture after 555 hours.
Give your answer in standard form to 3 significant figures.