A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1357800 can be evenly divided by 1 2 3 4 5 6 8 10 12 15 20 24 25 30 31 40 50 60 62 73 75 93 100 120 124 146 150 155 186 200 219 248 292 300 310 365 372 438 465 584 600 620 730 744 775 876 930 1,095 1,240 1,460 1,550 1,752 1,825 1,860 2,190 2,263 2,325 2,920 3,100 3,650 3,720 4,380 4,526 4,650 5,475 6,200 6,789 7,300 8,760 9,052 9,300 10,950 11,315 13,578 14,600 18,104 18,600 21,900 22,630 27,156 33,945 43,800 45,260 54,312 56,575 67,890 90,520 113,150 135,780 169,725 226,300 271,560 339,450 452,600 678,900 and 1,357,800, with no remainder.
Since 1,357,800 cannot be divided by just 1 and 1,357,800, it is not a prime number.