Pantomath

A pantomath is a person who wants to know or knows everything. The word itself is not to be found in common online English dictionaries, the OED, dictionaries of obscure words, or dictionaries of neologisms.

Etymology
A pantomath (pantomathēs, παντομαθής, meaning "having learnt all", from the Greek roots παντ- "all", "every" and the root μαθ-, meaning "learning", "understanding") is a person whose astonishingly wide interests and knowledge span the entire range of the arts and sciences.

Uses
Pantomath is typically used to convey the sense that a great individual has achieved a pinnacle of learning, that an "automath" has taken autodidacticism to an endpoint. As an example, the obscure and rare term seems to have been applied to those with an astonishingly wide knowledge and interests by these two authors from different eras: Jonathan Miller has been called a pantomath, as has Rupert Hart-Davis.

Reference

 * Wikipedia