21443828 has 12 divisors (see below), whose sum is σ = 42887712. Its totient is φ = 9190200.

The previous prime is 21443827. The next prime is 21443881. The reversal of 21443828 is 82834412.

21443828 is an admirable number.

It is a junction number, because it is equal to n+sod(n) for n = 21443794 and 21443803.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21443827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 382898 + ... + 382953.

It is an arithmetic number, because the mean of its divisors is an integer number (3573976).

Almost surely, 2^21443828 is an apocalyptic number.

21443828 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21443828 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21443828 is a wasteful number, since it uses less digits than its factorization.

21443828 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 765862 (or 765860 counting only the distinct ones).

The product of its digits is 12288, while the sum is 32.

The square root of 21443828 is about 4630.7481037085. The cubic root of 21443828 is about 277.8225149397.

The spelling of 21443828 in words is "twenty-one million, four hundred forty-three thousand, eight hundred twenty-eight".