21252 divided by its sum of digits (12) gives a palindrome (1771).
Subtracting from 21252 its product of digits (40), we obtain a palindrome (21212).
Adding to 21252 its reverse (25212), we get a palindrome (46464).
21252 is an esthetic number in base 13, because in such base its adjacent digits differ by 1.
It is an alternating number because its digits alternate between even and odd.
It is an unprimeable number.
221252 is an apocalyptic number.
21252 is a gapful number since it is divisible by the number (22) 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 21252, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32256).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
21252 is a wasteful number, since it uses less digits than its factorization.
21252 is an odious number, because the sum of its binary digits is odd.
The square root of 21252 is about 145.7806571531. The cubic root of 21252 is about 27.6991602225.
The spelling of 21252 in words is "twenty-one thousand, two hundred fifty-two".