10929 - You can say 11
Determine if a large positive number is a multiple if 11.
If ABCDEFG is multiple of 11, then A-B+C-D+E-F+G... is also divisible by 11. Otherwise ABCDEFG isn't a multiple of 11.
Another method (similar to long-division on pen and paper) is to read digits one-by-one, and apply the modulus; this will work on any arbitrary number, while using primitive types. A number N is divisible by 11 if the final digit results in no remainder.
Numbers can have leading zeros.
112233 30800 2937 323455693 5038297 112234 0
112233 is a multiple of 11. 30800 is a multiple of 11. 2937 is a multiple of 11. 323455693 is a multiple of 11. 5038297 is a multiple of 11. 112234 is not a multiple of 11.