A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 5428836 can be evenly divided by 1 2 3 4 6 7 9 12 14 18 21 27 28 36 42 43 54 63 84 86 108 126 129 167 172 189 252 258 301 334 378 387 501 516 602 668 756 774 903 1,002 1,161 1,169 1,204 1,503 1,548 1,806 2,004 2,322 2,338 2,709 3,006 3,507 3,612 4,509 4,644 4,676 5,418 6,012 7,014 7,181 8,127 9,018 10,521 10,836 14,028 14,362 16,254 18,036 21,042 21,543 28,724 31,563 32,508 42,084 43,086 50,267 63,126 64,629 86,172 100,534 126,252 129,258 150,801 193,887 201,068 258,516 301,602 387,774 452,403 603,204 775,548 904,806 1,357,209 1,809,612 2,714,418 and 5,428,836, with no remainder.
Since 5,428,836 cannot be divided by just 1 and 5,428,836, it is not a prime number.