Listen to Piano Concerto No. 21 in C Major, K. 467: I. Allegro maestoso online. Piano Concerto No. 21 in C Major, K. 467: I. Allegro maestoso is an English language song and is sung by Guido Cantelli, Walter Gieseking and New York Philharmonic Orchestra. Piano Concerto No. 21 in C Major, K. 467: I. Allegro maestoso, from the album Best of Classical Music, was released in the year 2014. The duration of the song is 14:31. Download English songs online from JioSaavn.