21696928 has 48 divisors (see below), whose sum is σ = 47519136. Its totient is φ = 9667840.

The previous prime is 21696923. The next prime is 21696937. The reversal of 21696928 is 82969612.

It is not an unprimeable number, because it can be changed into a prime (21696923) 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, 18075 + ... + 19237.

It is an arithmetic number, because the mean of its divisors is an integer number (989982).

Almost surely, 2^21696928 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 21696928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23759568).

21696928 is an abundant number, since it is smaller than the sum of its proper divisors (25822208).

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

21696928 is a wasteful number, since it uses less digits than its factorization.

21696928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1237 (or 1229 counting only the distinct ones).

The product of its digits is 93312, while the sum is 43.

The square root of 21696928 is about 4657.9961356789. The cubic root of 21696928 is about 278.9112824554.

The spelling of 21696928 in words is "twenty-one million, six hundred ninety-six thousand, nine hundred twenty-eight".