21866304 has 56 divisors (see below), whose sum is σ = 58834528. Its totient is φ = 7165440.

The previous prime is 21866303. The next prime is 21866311. The reversal of 21866304 is 40366812.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21866303) 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, 10779 + ... + 12645.

Almost surely, 2^21866304 is an apocalyptic number.

21866304 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21866304, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29417264).

21866304 is an abundant number, since it is smaller than the sum of its proper divisors (36968224).

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

21866304 is a wasteful number, since it uses less digits than its factorization.

21866304 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1943 (or 1933 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 30.

The square root of 21866304 is about 4676.1419995548. The cubic root of 21866304 is about 279.6351711074.

The spelling of 21866304 in words is "twenty-one million, eight hundred sixty-six thousand, three hundred four".