21210112 has 88 divisors (see below), whose sum is σ = 53058240. Its totient is φ = 8232960.

The previous prime is 21210109. The next prime is 21210151. The reversal of 21210112 is 21101212.

It is a tau number, because it is divible by the number of its divisors (88).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 78714 + ... + 78982.

Almost surely, 2^21210112 is an apocalyptic number.

21210112 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 21210112, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26529120).

21210112 is an abundant number, since it is smaller than the sum of its proper divisors (31848128).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21210112 is a wasteful number, since it uses less digits than its factorization.

21210112 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 307 (or 289 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

The square root of 21210112 is about 4605.4437354070. The cubic root of 21210112 is about 276.8094977083.

Adding to 21210112 its reverse (21101212), we get a palindrome (42311324).

Subtracting from 21210112 its reverse (21101212), we obtain a square (108900 = 330²).

The spelling of 21210112 in words is "twenty-one million, two hundred ten thousand, one hundred twelve".