1375 = 5 x 5 x 5 x 11.
1375 is a decagonal pyramidal number (A007585).
1375 is 111133 in base 4.
1375 is the smaller of two consecutive numbers each divisible by a cube (A068140). It is also the smallest of three consecutive numbers divisible by a square (A070258).
13752 = 1,890,625 contains exactly seven different digits (A054035).
Source: What's Special About This Number?