21823620 has 144 divisors (see below), whose sum is σ = 76684608. Its totient is φ = 4596480.

The previous prime is 21823589. The next prime is 21823621. The reversal of 21823620 is 2632812.

It is not an unprimeable number, because it can be changed into a prime (21823621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 37935 + ... + 38505.

It is an arithmetic number, because the mean of its divisors is an integer number (532532).

Almost surely, 2^21823620 is an apocalyptic number.

21823620 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 21823620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38342304).

21823620 is an abundant number, since it is smaller than the sum of its proper divisors (54860988).

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

21823620 is a wasteful number, since it uses less digits than its factorization.

21823620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 610 (or 601 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 21823620 is about 4671.5757512856. The cubic root of 21823620 is about 279.4530991459.

The spelling of 21823620 in words is "twenty-one million, eight hundred twenty-three thousand, six hundred twenty".