A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 8690688 can be evenly divided by 1 2 3 4 6 8 9 12 16 18 23 24 32 36 41 46 48 64 69 72 82 92 96 123 128 138 144 164 184 192 207 246 256 276 288 328 368 369 384 414 492 512 552 576 656 736 738 768 828 943 984 1,024 1,104 1,152 1,312 1,472 1,476 1,536 1,656 1,886 1,968 2,208 2,304 2,624 2,829 2,944 2,952 3,072 3,312 3,772 3,936 4,416 4,608 5,248 5,658 5,888 5,904 6,624 7,544 7,872 8,487 8,832 9,216 10,496 11,316 11,776 11,808 13,248 15,088 15,744 16,974 17,664 20,992 22,632 23,552 23,616 26,496 30,176 31,488 33,948 35,328 41,984 45,264 47,232 52,992 60,352 62,976 67,896 70,656 90,528 94,464 105,984 120,704 125,952 135,792 181,056 188,928 211,968 241,408 271,584 362,112 377,856 482,816 543,168 724,224 965,632 1,086,336 1,448,448 2,172,672 2,896,896 4,345,344 and 8,690,688, with no remainder.
Since 8,690,688 cannot be divided by just 1 and 8,690,688, it is not a prime number.