Q: Is 521,668 a Prime Number?
A: No, 521,668 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 521668 can be evenly divided by 1 2 4 7 14 28 31 62 124 217 434 601 868 1,202 2,404 4,207 8,414 16,828 18,631 37,262 74,524 130,417 260,834 and 521,668, with no remainder.
Since 521,668 cannot be divided by just 1 and 521,668, it is not a prime number.