Multipling 21875 by its product of digits (560), we get a square (12250000 = 35002).
Subtracting 21875 from its reverse (57812), we obtain a cube (35937 = 333).
It is a self number, because there is not a number n which added to its sum of digits gives 21875.
21875 is a Friedman number, since it can be written as 5^(7-2)*(8-1), using all its digits and the basic arithmetic operations.
221875 is an apocalyptic number.
21875 is a gapful number since it is divisible by the number (25) formed by its first and last digit.
21875 is an frugal number, since it uses more digits than its factorization.
21875 is an odious number, because the sum of its binary digits is odd.
The square root of 21875 is about 147.9019945775. The cubic root of 21875 is about 27.9672235520.
The spelling of 21875 in words is "twenty-one thousand, eight hundred seventy-five".