A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 4368168 can be evenly divided by 1 2 3 4 6 7 8 9 12 14 18 21 24 27 28 36 42 54 56 63 72 81 84 107 108 126 162 168 189 214 216 243 252 321 324 378 428 486 504 567 642 648 729 749 756 856 963 972 1,134 1,284 1,458 1,498 1,512 1,701 1,926 1,944 2,247 2,268 2,568 2,889 2,916 2,996 3,402 3,852 4,494 4,536 5,103 5,778 5,832 5,992 6,741 6,804 7,704 8,667 8,988 10,206 11,556 13,482 13,608 17,334 17,976 20,223 20,412 23,112 26,001 26,964 34,668 40,446 40,824 52,002 53,928 60,669 69,336 78,003 80,892 104,004 121,338 156,006 161,784 182,007 208,008 242,676 312,012 364,014 485,352 546,021 624,024 728,028 1,092,042 1,456,056 2,184,084 and 4,368,168, with no remainder.
Since 4,368,168 cannot be divided by just 1 and 4,368,168, it is not a prime number.