A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 8602128 can be evenly divided by 1 2 3 4 6 8 9 12 16 18 24 31 36 41 47 48 62 72 82 93 94 123 124 141 144 164 186 188 246 248 279 282 328 369 372 376 423 492 496 558 564 656 738 744 752 846 984 1,116 1,128 1,271 1,457 1,476 1,488 1,692 1,927 1,968 2,232 2,256 2,542 2,914 2,952 3,384 3,813 3,854 4,371 4,464 5,084 5,781 5,828 5,904 6,768 7,626 7,708 8,742 10,168 11,439 11,562 11,656 13,113 15,252 15,416 17,343 17,484 20,336 22,878 23,124 23,312 26,226 30,504 30,832 34,686 34,968 45,756 46,248 52,452 59,737 61,008 69,372 69,936 91,512 92,496 104,904 119,474 138,744 179,211 183,024 209,808 238,948 277,488 358,422 477,896 537,633 716,844 955,792 1,075,266 1,433,688 2,150,532 2,867,376 4,301,064 and 8,602,128, with no remainder.
Since 8,602,128 cannot be divided by just 1 and 8,602,128, it is not a prime number.