The 2000 calories sounds like it could be your basal metabolic rate. If you put your stats in on a TDEE calculator it should be fairly accurate, at least mine is for my weight and height. Your basal metabolic rate is like a rough guide to the number of calories your body needs to sustain itself.

You do realise that 17,000 steps is actually quite a lot of steps! 10,000 steps is roughly 5 miles and the average number of steps of a sedentary person is between 1000 - 3000.

Are your steps through running or just walking? Because if it's walking than that seems like quite a high number of calories to be burning. As an example my Basal Metabolic Rate (So my resting calories burnt on Garmin) is about 2400. Yesterday I burnt about 3600 calories. I did roughly 10,000 steps and most of that was through running since I work in an office and do less than 2000 steps outside of exercise. If i walked 10,000 steps rather than ran it my burnt calories at the end of the day would be somewhere nearer 3000.