I looked at the sofware link, and it looks very similar to the Map My Ride software that I used to have on my I-Phone. Yes, it it is very possible that you burned 2100 calories. It all has to do with your height, weight, calculated BMI, (unless you know it), lactate threshold, and HR. We rode our tandem yesterday on a 28 mile loop. Climb was 1700' and duration was 2:09 with average speed of 13.2. I burned 1873 calories with an average HR of 111. The day before, I did a harder ride. 48 miles, 2400' of climbing, average speed of 17.1 and average HR of 127 and I burned 3300 calories.
If you are really into ride statistics, I suggest you consider a Garmin or similar computer. The problem with phone software, unless you have a satellite phone, is that you are limited to cell tower connections (someone correct me if I am wrong). If you ride anywhere that you can't get cell phone reception, you can't get data, including GPS. It is really a pain to return home and find that you got dropped on your cell connection, so there is only data to the point of the drop. Another drawback is that your cell phone is always on, so you use up your battery really fast. After just a few rides, I was very disappointed with the Map My Ride app. My Garmin 305 gives me all the data I need and will last for 13+ hours before the battery dies. It is a true GPS running off the satellites.