How many 16x16 pavers cover 390 square feet?

The answer depends on the measurement units used for 16x16. The answer also depends on the shape of the 390 sq ft area to be covered because the more irregular the shape, the greater the number of pavers you will need to cut. That is likely to result in some breakage. Furthermore, you may not want to use all the offcuts since that will make part of the area into a mosaic.