List the numbers 0-999999 in two columns, one ascending and one descending:

The sum of the digits in each row is 54, and there are 1 million rows, giving a total of 54 million for the two columns. Thus the total for one column is 27 million, and adding 1 for the number 1,000,000 itself gives a final sum of 27,000,001.

Bonus: In Number Freak (2009), Derrick Niederman notes that if you write out the first 500,000,000 positive integers, you’ll write the figure 1 precisely 500,000,000 times.