There are two different algorithms of this sort: the Number recognition and the Exact match search algorithm.
The Number recognition search algorithm compares the search query to the product number of the product, as it is known in Tweakwise. You can find the product number in Catalog > Items > General > ID:
You can choose whether you want to enable this algorithm or not. Read more about this functionality here:
The number recognition search algorithm compares the entered search term with the item number associated with the product. This involves number values only.
It looks for an exact match here, so the number entered must match the property exactly. However, the algorithm does take into account the following punctuation marks:
( ) Space
(-) Hyphen
(_) Underscore
(.) Dot
For example, if someone searches for 101-29 , the algorithm will also search for 10129.