Q: Is 640,640 a Prime Number?
A: No, 640,640 is not a prime number.
A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 640640 can be evenly divided by 1 2 4 5 7 8 10 11 13 14 16 20 22 26 28 32 35 40 44 52 55 56 64 65 70 77 80 88 91 104 110 112 128 130 140 143 154 160 176 182 208 220 224 260 280 286 308 320 352 364 385 416 440 448 455 520 560 572 616 640 704 715 728 770 832 880 896 910 1,001 1,040 1,120 1,144 1,232 1,408 1,430 1,456 1,540 1,664 1,760 1,820 2,002 2,080 2,240 2,288 2,464 2,860 2,912 3,080 3,520 3,640 4,004 4,160 4,480 4,576 4,928 5,005 5,720 5,824 6,160 7,040 7,280 8,008 8,320 9,152 9,856 10,010 11,440 11,648 12,320 14,560 16,016 18,304 20,020 22,880 24,640 29,120 32,032 40,040 45,760 49,280 58,240 64,064 80,080 91,520 128,128 160,160 320,320 and 640,640, with no remainder.
Since 640,640 cannot be divided by just 1 and 640,640, it is not a prime number.