Let's start with some conversions:

1 km = 0.6214 mi

1 mi = 5,280 ft

1 ft = 12 in

The average hamburger bun in the US is 4 inches, from what I can find online. Thus,

1,100 km * [0.6214 mi / 1 km] * [5,280 ft / 1 mi] * [12 in / 1 ft] * [1 bun / 4 in] = 1.08272736 * 10^7 buns

So, to answer your question, it's about 10,827,273.6 hamburgers.