15. On a long strip of paper, the numbers $1, 2, 3, \ldots, n$ are written in sequence. The long strip is cut into five segments, each containing some consecutive natural numbers (the digits of a single number are not split between different segments). We calculated the average of the numbers in these five segments, which are $1234, 345, 128, 19$, and $9.5$ (the order of these five numbers is scrambled). Therefore, $\mathbf{n}=$ $\qquad$ -
【Answer】2014
Analysis: The average of 1 to 18 is $9.5$, the average of 19 is 19, the average of 20 to 236 is 128, the average of 237 to 453 is 345, and the average of 454 to 2014 is 1234.
Average $=[$ (first term + last term) $\times$ number of terms $\div 2]$ number of terms, so the last term can be directly calculated.