When the sun becomes a white dwarf why will it take SO long to cool off?

I've read about the sun's life cycle. Apparently, when the sun becomes
a white dwarf, it will take at least a trillion years to completely
cool off. Why such a long time?

It's kind of like the same reason that big animals retain warmth better
in cold climates than small animals: they have more bulk retaining heat
compared to surface needed to radiate heat.

A white dwarf just doesn't have much radiating surface compared to the
bajillions [1] of tons of super-hot star stuff in its guts.

Further, it takes a long time for that heat to crawl from the interior
to the surface. The bulk of a star acts like a thick layer of
insulation over the hot core. Note the third paragraph in this link:
http://en.wikipedia.org/wiki/Sun#Core

Estimates suggest it takes 17,000 to 50 million years for a photon
generated in the core to crawl to the surface. While a white dwarf may
no longer be sustaining fusion, the heat in its interior just can't
radiate fast.

[1] Yes, bajillion is a technical term.

Mike Miller