What is the sum of all positive factors of256?? Share with your friends Share 1 Anita Gupta answered this Dear student, The factors of the number 256 are: 1, 2, 4, 8, 16, 32, 64, 128, 256. If we add them up, 1+2+4+8+16+32+64+128+256 we will get the total of 511. Regards 2 View Full Answer