Negri comma
16875/16384 is the 51.120 cent interval called the negri comma or double augmentation diesis. It is the amount by which four major thirds exceed three fourths, that is, (5/4)4/(4/3)3, and is also the amount by which three diatonic semitones (16/15) fall short of a major third, that is, (5/4)/(16/15)3. Tempering it out leads to 5-limit negri temperament, which is closely associated with 19edo.