A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 4056096 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 96 132 138 167 176 184 253 264 276 334 352 368 501 506 528 552 668 736 759 1,002 1,012 1,056 1,104 1,336 1,518 1,837 2,004 2,024 2,208 2,672 3,036 3,674 3,841 4,008 4,048 5,344 5,511 6,072 7,348 7,682 8,016 8,096 11,022 11,523 12,144 14,696 15,364 16,032 22,044 23,046 24,288 29,392 30,728 42,251 44,088 46,092 58,784 61,456 84,502 88,176 92,184 122,912 126,753 169,004 176,352 184,368 253,506 338,008 368,736 507,012 676,016 1,014,024 1,352,032 2,028,048 and 4,056,096, with no remainder.
Since 4,056,096 cannot be divided by just 1 and 4,056,096, it is not a prime number.