21212112 has 40 divisors (see below), whose sum is σ = 54974656. Its totient is φ = 7047936.

The previous prime is 21212111. The next prime is 21212119. The reversal of 21212112 is 21121212.

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

It is a nude number because it is divisible by every one of its digits and also a Zuckerman number because it is divisible by the product of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212111) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21453 + ... + 22419.

Almost surely, 2^21212112 is an apocalyptic number.

It is an amenable number.

21212112 is an abundant number, since it is smaller than the sum of its proper divisors (33762544).

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

21212112 is a wasteful number, since it uses less digits than its factorization.

21212112 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1435 (or 1429 counting only the distinct ones).

The product of its digits is 16, while the sum is 12.

The square root of 21212112 is about 4605.6608646317. The cubic root of 21212112 is about 276.8181979861.

Adding to 21212112 its reverse (21121212), we get a palindrome (42333324).

It can be divided in two parts, 212121 and 12, that multiplied together give a palindrome (2545452).

The spelling of 21212112 in words is "twenty-one million, two hundred twelve thousand, one hundred twelve".