21864928 has 48 divisors (see below), whose sum is σ = 45102960. Its totient is φ = 10423296.

The previous prime is 21864923. The next prime is 21864959. The reversal of 21864928 is 82946812.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21864923) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 69700 + ... + 70012.

It is an arithmetic number, because the mean of its divisors is an integer number (939645).

Almost surely, 2^21864928 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 21864928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22551480).

21864928 is an abundant number, since it is smaller than the sum of its proper divisors (23238032).

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

21864928 is a wasteful number, since it uses less digits than its factorization.

21864928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 419 (or 411 counting only the distinct ones).

The product of its digits is 55296, while the sum is 40.

The square root of 21864928 is about 4675.9948674052. The cubic root of 21864928 is about 279.6293053688.

The spelling of 21864928 in words is "twenty-one million, eight hundred sixty-four thousand, nine hundred twenty-eight".