# What is this special type of factor called?

I'm wondering if there's a special term for the following:

The (special factor) of a number $x$ is a pair of numbers that multiply to give $x$ but has the smallest difference compared to other factors of $x$

The (special factor) of $140$ is $14*10$
The (special factor) of $36$ is $6*6$ (in other words, not $9*4$ as $6-6 = 0$)
The (special factor) of $660$ is $22*30$

Is there a terminology for this special factor?

-
You could call it/them the median factor/s; they're exactly in the middle of the sequence of factors. –  joriki Oct 11 '11 at 12:45
they are also the divisors closest to $\sqrt{x}$ –  ratchet freak Oct 11 '11 at 12:47