Riverwalk
Polymath doesn't mean having a wide range of interests, and it's unusual for someone to claim this attribute - it's for others to describe someone as such.
I’m glad you point this out Riverwalk
I was too gobsmacked at SD’s description of himself and claim to be a polymath
In case there is any doubt-
You can think of a polymath as a classic "Renaissance man." Imagine Leonardo da Vinci, for example, who was not only an amazing artist, but also an engineer, inventor, mathematician, and much more. When a person's knowledge covers many different areas, he or she is a polymath. The Greek word for it is polymathes, "having learned much," with poly meaning "much," and manthanein meaning "learn."
In short,
Definition of polymath
(noun ) person of great and varied learning