A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 2055096 can be evenly divided by 1 2 3 4 6 8 9 12 17 18 23 24 34 36 46 51 68 69 72 73 92 102 136 138 146 153 184 204 207 219 276 292 306 391 408 414 438 552 584 612 657 782 828 876 1,173 1,224 1,241 1,314 1,564 1,656 1,679 1,752 2,346 2,482 2,628 3,128 3,358 3,519 3,723 4,692 4,964 5,037 5,256 6,716 7,038 7,446 9,384 9,928 10,074 11,169 13,432 14,076 14,892 15,111 20,148 22,338 28,152 28,543 29,784 30,222 40,296 44,676 57,086 60,444 85,629 89,352 114,172 120,888 171,258 228,344 256,887 342,516 513,774 685,032 1,027,548 and 2,055,096, with no remainder.
Since 2,055,096 cannot be divided by just 1 and 2,055,096, it is not a prime number.