21840768 has 48 divisors (see below), whose sum is σ = 62852400. Its totient is φ = 7279872.

The previous prime is 21840757. The next prime is 21840773. The reversal of 21840768 is 86704812.

It is a tau number, because it is divible by the number of its divisors (48).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8328 + ... + 10631.

It is an arithmetic number, because the mean of its divisors is an integer number (1309425).

Almost surely, 2^21840768 is an apocalyptic number.

It is an amenable number.

21840768 is an abundant number, since it is smaller than the sum of its proper divisors (41011632).

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

21840768 is a wasteful number, since it uses less digits than its factorization.

21840768 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18979 (or 18964 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 36.

The square root of 21840768 is about 4673.4107459114. The cubic root of 21840768 is about 279.5262737944.

The spelling of 21840768 in words is "twenty-one million, eight hundred forty thousand, seven hundred sixty-eight".