altogether vs on the whole

altogether is a noun but on the whole is not a noun.

Word	Noun	Adjective	Verb	Adverb
altogether	Yes	No	No	Yes
on the whole	No	No	No	Yes

As adverbs, altogether and on the whole are synonyms defined as:

altogether and on the whole: with everything considered (and neglecting details)

Other synonyms of altogether include all in all, tout ensemble.

altogether (noun)	on the whole (noun)
informal terms for nakedness

altogether (adverb)	on the whole (adverb)
with everything included or counted	with everything considered (and neglecting details)
with everything considered (and neglecting details)
to a complete degree or to the full or entire extent; Completely or entirely