A 5 digit no. is reversed.the original no. is subtracted from it.then the greatest prime factor of the difference is?

Let number be abcde
Value will be 10000a + 1000b + 100c + 10d + e
Reversed number will be 10000e + 1000d + 100c + 10b + a

Sbutracting we get ( 9999e + 990d –990b- 9999a)= 11*9 ( 101e + 10d –10b – 101a)
So 11 is highest prime factor.