Q: Is 1,621,640 a Prime Number?
A: No, 1,621,640 is not a prime number.
A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1621640 can be evenly divided by 1 2 4 5 8 10 20 40 71 142 284 355 568 571 710 1,142 1,420 2,284 2,840 2,855 4,568 5,710 11,420 22,840 40,541 81,082 162,164 202,705 324,328 405,410 810,820 and 1,621,640, with no remainder.
Since 1,621,640 cannot be divided by just 1 and 1,621,640, it is not a prime number.