Professor Layton Wiki
Professor Layton Wiki
Massive Gemstones It All Adds Up Black and White Balls

It All Adds Up is a weekly puzzle in Professor Layton and the Unwound Future.


Aside from 28 itself, the number 28 is divisible by 1, 2, 4, 7, and 14.

When you add these numbers together, you get 1 + 2 + 4 + 7 + 14 = 28. Neat, huh! They add up to the original number.

Now for the puzzle part:

What is the smallest number for which the sum of its divisors (not including the number itself) equals the original number?


Click a Tab to reveal the Hint.

The answer is a single-digit number.



Too bad!

Don't be intimidated by the fact that this is a calculation problem. Just think about it for a bit. It's easier than you might expect at first.


Nice work!

The answer is 6.

The number 6 is divisible by 1, 2, 3, and 6, so if you don't include 6 in the sum, you get 1 + 2+ 3 = 6!


A big thanks to