Q: Is 400,005 a Prime Number?
A: No, 400,005 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 400005 can be evenly divided by 1 3 5 9 15 27 45 135 2,963 8,889 14,815 26,667 44,445 80,001 133,335 and 400,005, with no remainder.
Since 400,005 cannot be divided by just 1 and 400,005, it is not a prime number.