21021112 has 64 divisors (see below), whose sum is σ = 48522240. Its totient is φ = 8332800.

The previous prime is 21021107. The next prime is 21021127. The reversal of 21021112 is 21112012.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 67437 + ... + 67747.

It is an arithmetic number, because the mean of its divisors is an integer number (758160).

Almost surely, 2^21021112 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 21021112, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24261120).

21021112 is an abundant number, since it is smaller than the sum of its proper divisors (27501128).

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

21021112 is a wasteful number, since it uses less digits than its factorization.

21021112 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 412 (or 408 counting only the distinct ones).

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

The square root of 21021112 is about 4584.8786243477. The cubic root of 21021112 is about 275.9848412875.

Adding to 21021112 its reverse (21112012), we get a palindrome (42133124).

The spelling of 21021112 in words is "twenty-one million, twenty-one thousand, one hundred twelve".