Is there a term for individuals who can "visualize" numbers and advanced mathematics? I recently saw an episode of 60 Minutes about Jacob Barnett, a 13 year old boy who is currently attending advanced physics classes at a local university and was portrayed by the show as being a child prodigy/genius. In the interview, he demonstrates how he's able to perform mathematical transformations in his head by visualizing the numbers as colored shapes. As he explains in the linked clip:


  This is 2 * 27:
  


He visualizes multiplying 2 by 27 as a series of colored triangles.

Is this a known phenomenon, and if so, does it have a name? Do other individuals visualize mathematics like this? Or is this just a 12-year old kid... embellishing (to be polite) his thought process?
Sounds like a form of Synesthesia, in particular it sounds like Number Form Synesthesia mixed with Grapheme-color Synesthesia:


  A number form is a mental map of numbers, which automatically and involuntarily appears whenever someone who experiences number-forms thinks of numbers. Number forms were first documented and named by Francis Galton in "The Visions of Sane Persons". Later research has identified them as a type of synesthesia. In particular, it has been suggested that number-forms are a result of "cross-activation" between regions of the parietal lobe that are involved in numerical cognition and spatial cognition


It doesn't seem exactly like what he does but it could be a form of it. It's hard to imagine just how it would be to perceive the world as a synesthesic person does.

It sounds like he's learned to apply his visual-spatial skills to "arrange" the number forms to aid his calculations.

Synesthesia is covered in detail in the book Synesthesia: a union of the senses, though I'm not aware of any specific case studies on individuals with this exact set of skills.

A term to describe people with Synestesia is Synesthesic.