A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 951048 can be evenly divided by 1 2 3 4 6 7 8 9 12 14 17 18 21 24 27 28 34 36 37 42 51 54 56 63 68 72 74 84 102 108 111 119 126 136 148 153 168 189 204 216 222 238 252 259 296 306 333 357 378 408 444 459 476 504 518 612 629 666 714 756 777 888 918 952 999 1,036 1,071 1,224 1,258 1,332 1,428 1,512 1,554 1,836 1,887 1,998 2,072 2,142 2,331 2,516 2,664 2,856 3,108 3,213 3,672 3,774 3,996 4,284 4,403 4,662 5,032 5,661 6,216 6,426 6,993 7,548 7,992 8,568 8,806 9,324 11,322 12,852 13,209 13,986 15,096 16,983 17,612 18,648 22,644 25,704 26,418 27,972 33,966 35,224 39,627 45,288 52,836 55,944 67,932 79,254 105,672 118,881 135,864 158,508 237,762 317,016 475,524 and 951,048, with no remainder.
Since 951,048 cannot be divided by just 1 and 951,048, it is not a prime number.