We're looking at the stats page of an email message and see the Total Opens are higher that Total Recipients.
Total Opens includes Forwarded Opens, so that could explain the discrepancy. If the number is still higher than recipients, then it could also be due to some constituents opening the email message on multiple times. To get the true amount of unique opens, you can run an Email Message Open report. When you have the results in Excel, you can use the Remove Duplicates function.