7
12346-987654 = -975308
12346
yes 12345 is a prime number
It can be divided by 3 as in 12345/3=4115, but not 9 as in 12345/9=1371.6666666666666.
180 * * * * * Wrong! There are 6: 12345, 12346, 12356, 12456, 13456 and 23456. And that is it! No more.
7
34
1 and 2.
823x15=12345
12346-987654 = -975308
12346
It is not possible to determine the rule from only one number!
yes 12345 is a prime number
12346 + 98764 = 111,110
12346
12345