A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3191112 can be evenly divided by 1 2 3 4 6 8 9 12 18 23 24 36 41 46 47 69 72 82 92 94 123 138 141 164 184 188 207 246 276 282 328 369 376 414 423 492 552 564 738 828 846 943 984 1,081 1,128 1,476 1,656 1,692 1,886 1,927 2,162 2,829 2,952 3,243 3,384 3,772 3,854 4,324 5,658 5,781 6,486 7,544 7,708 8,487 8,648 9,729 11,316 11,562 12,972 15,416 16,974 17,343 19,458 22,632 23,124 25,944 33,948 34,686 38,916 44,321 46,248 67,896 69,372 77,832 88,642 132,963 138,744 177,284 265,926 354,568 398,889 531,852 797,778 1,063,704 1,595,556 and 3,191,112, with no remainder.
Since 3,191,112 cannot be divided by just 1 and 3,191,112, it is not a prime number.