It is 7007. All odd numbers have their last digit as a odd number meaning that the last digit must be not divisible by 2
1,3,5,7 or 9
So 100015 is odd as the last digit is 5 which is odd
264784626847 is odd as the last digit is 7 which is odd
273784838 is not odd as the last digit is 8 which is even
