A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 697680 can be evenly divided by 1 2 3 4 5 6 8 9 10 12 15 16 17 18 19 20 24 27 30 34 36 38 40 45 48 51 54 57 60 68 72 76 80 85 90 95 102 108 114 120 135 136 144 152 153 170 171 180 190 204 216 228 240 255 270 272 285 304 306 323 340 342 360 380 408 432 456 459 510 513 540 570 612 646 680 684 720 760 765 816 855 912 918 969 1,020 1,026 1,080 1,140 1,224 1,292 1,360 1,368 1,520 1,530 1,615 1,710 1,836 1,938 2,040 2,052 2,160 2,280 2,295 2,448 2,565 2,584 2,736 2,907 3,060 3,230 3,420 3,672 3,876 4,080 4,104 4,560 4,590 4,845 5,130 5,168 5,814 6,120 6,460 6,840 7,344 7,752 8,208 8,721 9,180 9,690 10,260 11,628 12,240 12,920 13,680 14,535 15,504 17,442 18,360 19,380 20,520 23,256 25,840 29,070 34,884 36,720 38,760 41,040 43,605 46,512 58,140 69,768 77,520 87,210 116,280 139,536 174,420 232,560 348,840 and 697,680, with no remainder.
Since 697,680 cannot be divided by just 1 and 697,680, it is not a prime number.