Adding to 21288960 its sum of digits (36), we get a square (21288996 = 46142).
21288960 divided by its product of nonzero digits (13824) gives a triangular number (1540 = T55).
It is a tau number, because it is divible by the number of its divisors (384).
It is a congruent number.
It is an unprimeable number.
Almost surely, 221288960 is an apocalyptic number.
21288960 is a gapful number since it is divisible by the number (20) formed by its first and last digit.
It is an amenable number.
It is a practical number, because each smaller number is the sum of distinct divisors of 21288960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47174400).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
21288960 is a wasteful number, since it uses less digits than its factorization.
21288960 is an odious number, because the sum of its binary digits is odd.
The square root of 21288960 is about 4613.9960988280. The cubic root of 21288960 is about 277.1520840700.
The spelling of 21288960 in words is "twenty-one million, two hundred eighty-eight thousand, nine hundred sixty".