Question 734178
Are you trying to ask the reverse of the problem below?
 
Question 714806: Find a natural number for which if we move the first digit to the last place, the number that will emerge will be half of the original. 
 
From the number 105,263,157,894,736,842, if you take the 2 in the ones place and move to the front of the number, you get
210,526,315,789,473,684 which is double the original number.
When I worked through Question 714806, I found a formula, and suspected that there would be an infinite number of answers, but I showed the smallest answers I could find. I believe there is more than one answer to the reverse problem, but the other answers will be larger numbers.