21203112 has 64 divisors (see below), whose sum is σ = 61603200. Its totient is φ = 5955840.

The previous prime is 21203099. The next prime is 21203113. The reversal of 21203112 is 21130212.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is not an unprimeable number, because it can be changed into a prime (21203113) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9214 + ... + 11282.

It is an arithmetic number, because the mean of its divisors is an integer number (962550).

Almost surely, 2^21203112 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21203112, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30801600).

21203112 is an abundant number, since it is smaller than the sum of its proper divisors (40400088).

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

21203112 is a wasteful number, since it uses less digits than its factorization.

21203112 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2146 (or 2142 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 21203112 is about 4604.6837024925. The cubic root of 21203112 is about 276.7790424285.

Adding to 21203112 its reverse (21130212), we get a palindrome (42333324).

Subtracting from 21203112 its reverse (21130212), we obtain a square (72900 = 270²).

The spelling of 21203112 in words is "twenty-one million, two hundred three thousand, one hundred twelve".