A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 4396128 can be evenly divided by 1 2 3 4 6 8 11 12 16 22 23 24 32 33 44 46 48 66 69 88 92 96 132 138 176 181 184 253 264 276 352 362 368 506 528 543 552 724 736 759 1,012 1,056 1,086 1,104 1,448 1,518 1,991 2,024 2,172 2,208 2,896 3,036 3,982 4,048 4,163 4,344 5,792 5,973 6,072 7,964 8,096 8,326 8,688 11,946 12,144 12,489 15,928 16,652 17,376 23,892 24,288 24,978 31,856 33,304 45,793 47,784 49,956 63,712 66,608 91,586 95,568 99,912 133,216 137,379 183,172 191,136 199,824 274,758 366,344 399,648 549,516 732,688 1,099,032 1,465,376 2,198,064 and 4,396,128, with no remainder.
Since 4,396,128 cannot be divided by just 1 and 4,396,128, it is not a prime number.