4999999999999999+e 313
The number is technically infinite, but since it's the largest multiple of 5, we can't make it infinite. So in this case, use the line method to represent the instance that it will go on, and on, and on.
The last number will end in 6, because any multidigit number with all 0's after the number, minus 4, is that number followed by 6 in the ones place.