21311112 has 64 divisors (see below), whose sum is σ = 55486080. Its totient is φ = 6815232.

The previous prime is 21311111. The next prime is 21311113. The reversal of 21311112 is 21111312.

It is an interprime number because it is at equal distance from previous prime (21311111) and next prime (21311113).

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 not an unprimeable number, because it can be changed into a prime (21311111) 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, 91348 + ... + 91580.

It is an arithmetic number, because the mean of its divisors is an integer number (866970).

Almost surely, 2^21311112 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 21311112, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27743040).

21311112 is an abundant number, since it is smaller than the sum of its proper divisors (34174968).

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

21311112 is a wasteful number, since it uses less digits than its factorization.

21311112 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 382 (or 378 counting only the distinct ones).

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

The square root of 21311112 is about 4616.3959968790. The cubic root of 21311112 is about 277.2481799610.

Adding to 21311112 its reverse (21111312), we get a palindrome (42422424).

It can be divided in two parts, 21311 and 112, that multiplied together give a palindrome (2386832).

The spelling of 21311112 in words is "twenty-one million, three hundred eleven thousand, one hundred twelve".