This number is a prime.
Just showing those entries submitted by 'Beedle': (Click here to show all)
Divisibility test for 11: Combine the digits in order by alternating them with positive and negative signs. If the result is divisible by 11, then so is the original number. For example, 11 divides 90816 because 11 divides + 9 - 0 + 8 - 1 + 6. [Beedle]