A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 7398468 can be evenly divided by 1 2 3 4 6 7 9 11 12 14 17 18 21 22 28 33 34 36 42 44 51 63 66 68 77 84 99 102 119 126 132 153 154 157 187 198 204 231 238 252 306 308 314 357 374 396 462 471 476 561 612 628 693 714 748 924 942 1,071 1,099 1,122 1,309 1,386 1,413 1,428 1,683 1,727 1,884 2,142 2,198 2,244 2,618 2,669 2,772 2,826 3,297 3,366 3,454 3,927 4,284 4,396 5,181 5,236 5,338 5,652 6,594 6,732 6,908 7,854 8,007 9,891 10,362 10,676 11,781 12,089 13,188 15,543 15,708 16,014 18,683 19,782 20,724 23,562 24,021 24,178 29,359 31,086 32,028 36,267 37,366 39,564 47,124 48,042 48,356 56,049 58,718 62,172 72,534 74,732 88,077 96,084 108,801 112,098 117,436 145,068 168,147 176,154 205,513 217,602 224,196 264,231 336,294 352,308 411,026 435,204 528,462 616,539 672,588 822,052 1,056,924 1,233,078 1,849,617 2,466,156 3,699,234 and 7,398,468, with no remainder.
Since 7,398,468 cannot be divided by just 1 and 7,398,468, it is not a prime number.