21044844 has 72 divisors (see below), whose sum is σ = 56963088. Its totient is φ = 6528000.

The previous prime is 21044833. The next prime is 21044873. The reversal of 21044844 is 44844012.

It is a happy number.

21044844 is a `hidden beast` number, since 210 + 448 + 4 + 4 = 666.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 83719 + ... + 83969.

It is an arithmetic number, because the mean of its divisors is an integer number (791154).

Almost surely, 2^21044844 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 21044844, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28481544).

21044844 is an abundant number, since it is smaller than the sum of its proper divisors (35918244).

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

21044844 is a wasteful number, since it uses less digits than its factorization.

21044844 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 415 (or 410 counting only the distinct ones).

The product of its (nonzero) digits is 4096, while the sum is 27.

The square root of 21044844 is about 4587.4659671762. The cubic root of 21044844 is about 276.0886608670.

Adding to 21044844 its reverse (44844012), we get a palindrome (65888856).

It can be divided in two parts, 210 and 44844, that added together give a palindrome (45054).

The spelling of 21044844 in words is "twenty-one million, forty-four thousand, eight hundred forty-four".