How many pockets do they have?

8 pockets if you include the top openings on the cargo pockets (for cell phones & such) that quickly stash things behind the pockets.

The pants I'm wearing right now, are a size 44W but when I use the measuring tape, it seems like the pants have 49"W. How do I choose right size?

If you have more than 1 size 44W pants which fit you now, I'd suggets going one size larger in these. These slacks are less roomy than Wrangler's heavier-duty cargo pants AND these have a shorter waist...if you hike them up to have your belt just above hips, the inseam will be pulled-up right under your bum. If you have great legs, no problem. I much prefer the heavier and more roomy Wrangler Riggs Workwear Cargo Pant, although, for summer these lighter-weight pants under discussion would be better for casual use. The full-size belt loops are a positive thing for me. For any of the Wrangler pants, the "ripstop" models (certain colors only) are superior to the regular cotton fabric. Ripstop liiks and feels better and I believe is more durable.