A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1010988 can be evenly divided by 1 2 3 4 6 9 11 12 18 22 23 27 33 36 37 44 46 54 66 69 74 92 99 108 111 132 138 148 198 207 222 253 276 297 333 396 407 414 444 506 594 621 666 759 814 828 851 999 1,012 1,188 1,221 1,242 1,332 1,518 1,628 1,702 1,998 2,277 2,442 2,484 2,553 3,036 3,404 3,663 3,996 4,554 4,884 5,106 6,831 7,326 7,659 9,108 9,361 10,212 10,989 13,662 14,652 15,318 18,722 21,978 22,977 27,324 28,083 30,636 37,444 43,956 45,954 56,166 84,249 91,908 112,332 168,498 252,747 336,996 505,494 and 1,010,988, with no remainder.
Since 1,010,988 cannot be divided by just 1 and 1,010,988, it is not a prime number.