Adding to 21102 its reverse (20112), we get a palindrome (41214).
Subtracting from 21102 its reverse (20112), we obtain a triangular number (990 = T44).
It is a happy number.
It is a sphenic number, since it is the product of 3 distinct primes.
21102 is an admirable number.
It is a congruent number.
221102 is an apocalyptic number.
21102 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
21102 is a wasteful number, since it uses less digits than its factorization.
21102 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 3522.
The square root of 21102 is about 145.2652745841. The cubic root of 21102 is about 27.6338379344.
The spelling of 21102 in words is "twenty-one thousand, one hundred two", and thus it is an iban number.