Q: Is 1,688,421 a Prime Number?
A: No, 1,688,421 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 1688421 can be evenly divided by 1 3 7 21 37 41 53 111 123 159 259 287 371 777 861 1,113 1,517 1,961 2,173 4,551 5,883 6,519 10,619 13,727 15,211 31,857 41,181 45,633 80,401 241,203 562,807 and 1,688,421, with no remainder.
Since 1,688,421 cannot be divided by just 1 and 1,688,421, it is not a prime number.