Q: Is 21,870 a Prime Number?
A: No, 21,870 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 21870 can be evenly divided by 1 2 3 5 6 9 10 15 18 27 30 45 54 81 90 135 162 243 270 405 486 729 810 1,215 1,458 2,187 2,430 3,645 4,374 7,290 10,935 and 21,870, with no remainder.
Since 21,870 cannot be divided by just 1 and 21,870, it is not a prime number.