21458928 has 40 divisors (see below), whose sum is σ = 56147200. Its totient is φ = 7061184.

The previous prime is 21458909. The next prime is 21458929. The reversal of 21458928 is 82985412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21458929) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 963 + ... + 6621.

It is an arithmetic number, because the mean of its divisors is an integer number (1403680).

Almost surely, 2^21458928 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21458928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28073600).

21458928 is an abundant number, since it is smaller than the sum of its proper divisors (34688272).

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

21458928 is a wasteful number, since it uses less digits than its factorization.

21458928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5749 (or 5743 counting only the distinct ones).

The product of its digits is 46080, while the sum is 39.

The square root of 21458928 is about 4632.3782229002. The cubic root of 21458928 is about 277.8877106326.

The spelling of 21458928 in words is "twenty-one million, four hundred fifty-eight thousand, nine hundred twenty-eight".