This is the definitive American ragtime piece that brought syncopated music into the mainstream global consciousness. Its distinctive feature is the iconic 'Alexander' motive which acts as a rhythmic engine for the entire composition.
The technical challenge is maintaining strict stride piano left-hand accuracy while keeping the right hand rhythmically loose.
Comparable difficulty and character — good candidates for what to learn next.
Alexander's Ragtime Band is rated Henle level 4 of 9 — intermediate repertoire, roughly ABRSM grades 5–6. In the RCM system it corresponds to about level 6.
You should be comfortable at Henle level 4 — meaning you can already play level 3–4 pieces cleanly. Learning it one level early is possible as a stretch piece, but more than that usually leads to months of frustration.
A typical performance of Alexander's Ragtime Band lasts about 3 minutes.
Alexander's Ragtime Band is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.
Pieces at a comparable difficulty and character include Canto del guajiro by Ernesto Lecuona, Black and White Rag by George Botsford, Bacchus Galop by Hans Christian Lumbye — see the full similar-pieces list on this page.