21728696 has 24 divisors (see below), whose sum is σ = 44783760. Its totient is φ = 9876240.

The previous prime is 21728689. The next prime is 21728699. The reversal of 21728696 is 69682712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21728699) 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 5 ways as a sum of consecutive naturals, for example, 10256 + ... + 12191.

It is an arithmetic number, because the mean of its divisors is an integer number (1865990).

Almost surely, 2^21728696 is an apocalyptic number.

It is an amenable number.

21728696 is an abundant number, since it is smaller than the sum of its proper divisors (23055064).

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

21728696 is a wasteful number, since it uses less digits than its factorization.

21728696 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22475 (or 22460 counting only the distinct ones).

The product of its digits is 72576, while the sum is 41.

The square root of 21728696 is about 4661.4049384279. The cubic root of 21728696 is about 279.0473406220.

The spelling of 21728696 in words is "twenty-one million, seven hundred twenty-eight thousand, six hundred ninety-six".