21113844 has 24 divisors (see below), whose sum is σ = 50002848. Its totient is φ = 6932640.

The previous prime is 21113843. The next prime is 21113861. The reversal of 21113844 is 44831112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21113843) 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, 12327 + ... + 13934.

It is an arithmetic number, because the mean of its divisors is an integer number (2083452).

Almost surely, 2^21113844 is an apocalyptic number.

It is an amenable number.

21113844 is an abundant number, since it is smaller than the sum of its proper divisors (28889004).

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

21113844 is a wasteful number, since it uses less digits than its factorization.

21113844 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26335 (or 26333 counting only the distinct ones).

The product of its digits is 768, while the sum is 24.

The square root of 21113844 is about 4594.9803046368. The cubic root of 21113844 is about 276.3900701731.

Adding to 21113844 its reverse (44831112), we get a palindrome (65944956).

The spelling of 21113844 in words is "twenty-one million, one hundred thirteen thousand, eight hundred forty-four".