She's one of definitely.

She is.

She has the sales (BOTH ALBUM AND SINGLES)
She has the classic songs's musical impact
She has the #1s
She has the reinventions
She has the looks
She has the personality
She has the touring force
She has the memorable moments
She has the dramatic live and events
She has the performances now
She has the billion dollar voice
She has the musical influence in her peers
She has the iconic dresses
She has the iconic haircuts
She has the time left to keep proving herself... as she is just 26

I mean... lets be honest here

Yes obviously, every other pop girl is lacking in a major department. Beyonce can't sell a single to save her life, Katy can't tour outside of Australia and Adele has no celebrity power. Rihanna can literally do it all while also putting out better music than everyone else! Queen!