A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3313296 can be evenly divided by 1 2 3 4 6 7 8 9 12 14 16 18 19 21 24 28 36 38 42 48 56 57 63 72 76 84 112 114 126 133 144 152 168 171 173 228 252 266 304 336 342 346 399 456 504 519 532 684 692 798 912 1,008 1,038 1,064 1,197 1,211 1,368 1,384 1,557 1,596 2,076 2,128 2,394 2,422 2,736 2,768 3,114 3,192 3,287 3,633 4,152 4,788 4,844 6,228 6,384 6,574 7,266 8,304 9,576 9,688 9,861 10,899 12,456 13,148 14,532 19,152 19,376 19,722 21,798 23,009 24,912 26,296 29,064 29,583 39,444 43,596 46,018 52,592 58,128 59,166 69,027 78,888 87,192 92,036 118,332 138,054 157,776 174,384 184,072 207,081 236,664 276,108 368,144 414,162 473,328 552,216 828,324 1,104,432 1,656,648 and 3,313,296, with no remainder.
Since 3,313,296 cannot be divided by just 1 and 3,313,296, it is not a prime number.