21824920 has 96 divisors (see below), whose sum is σ = 56876400. Its totient is φ = 7471872.

The previous prime is 21824917. The next prime is 21824921. The reversal of 21824920 is 2942812.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21824921) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 464337 + ... + 464383.

Almost surely, 2^21824920 is an apocalyptic number.

21824920 is a gapful number since it is divisible by the number (20) 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 21824920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28438200).

21824920 is an abundant number, since it is smaller than the sum of its proper divisors (35051480).

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

21824920 is a wasteful number, since it uses less digits than its factorization.

21824920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 137 (or 86 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 21824920 is about 4671.7148885607. The cubic root of 21824920 is about 279.4586479017.

The spelling of 21824920 in words is "twenty-one million, eight hundred twenty-four thousand, nine hundred twenty".