21823228 has 72 divisors (see below), whose sum is σ = 47803392. Its totient is φ = 8670816.

The previous prime is 21823211. The next prime is 21823247. The reversal of 21823228 is 82232812.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a junction number, because it is equal to n+sod(n) for n = 21823196 and 21823205.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 211825 + ... + 211927.

It is an arithmetic number, because the mean of its divisors is an integer number (663936).

Almost surely, 2^21823228 is an apocalyptic number.

21823228 is a gapful number since it is divisible by the number (28) 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 21823228, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23901696).

21823228 is an abundant number, since it is smaller than the sum of its proper divisors (25980164).

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

21823228 is a wasteful number, since it uses less digits than its factorization.

21823228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 191 (or 182 counting only the distinct ones).

The product of its digits is 3072, while the sum is 28.

The square root of 21823228 is about 4671.5337952326. The cubic root of 21823228 is about 279.4514259394.

The spelling of 21823228 in words is "twenty-one million, eight hundred twenty-three thousand, two hundred twenty-eight".