A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 5211600 can be evenly divided by 1 2 3 4 5 6 8 10 12 15 16 20 24 25 30 40 43 48 50 60 75 80 86 100 101 120 129 150 172 200 202 215 240 258 300 303 344 400 404 430 505 516 600 606 645 688 808 860 1,010 1,032 1,075 1,200 1,212 1,290 1,515 1,616 1,720 2,020 2,064 2,150 2,424 2,525 2,580 3,030 3,225 3,440 4,040 4,300 4,343 4,848 5,050 5,160 6,060 6,450 7,575 8,080 8,600 8,686 10,100 10,320 12,120 12,900 13,029 15,150 17,200 17,372 20,200 21,715 24,240 25,800 26,058 30,300 34,744 40,400 43,430 51,600 52,116 60,600 65,145 69,488 86,860 104,232 108,575 121,200 130,290 173,720 208,464 217,150 260,580 325,725 347,440 434,300 521,160 651,450 868,600 1,042,320 1,302,900 1,737,200 2,605,800 and 5,211,600, with no remainder.
Since 5,211,600 cannot be divided by just 1 and 5,211,600, it is not a prime number.