A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3481800 can be evenly divided by 1 2 3 4 5 6 7 8 10 12 14 15 20 21 24 25 28 30 35 40 42 50 56 60 70 75 84 100 105 120 140 150 168 175 200 210 280 300 350 420 525 600 700 829 840 1,050 1,400 1,658 2,100 2,487 3,316 4,145 4,200 4,974 5,803 6,632 8,290 9,948 11,606 12,435 16,580 17,409 19,896 20,725 23,212 24,870 29,015 33,160 34,818 41,450 46,424 49,740 58,030 62,175 69,636 82,900 87,045 99,480 116,060 124,350 139,272 145,075 165,800 174,090 232,120 248,700 290,150 348,180 435,225 497,400 580,300 696,360 870,450 1,160,600 1,740,900 and 3,481,800, with no remainder.
Since 3,481,800 cannot be divided by just 1 and 3,481,800, it is not a prime number.