21732928 has 56 divisors (see below), whose sum is σ = 49784000. Its totient is φ = 9220608.

The previous prime is 21732917. The next prime is 21732943. The reversal of 21732928 is 82923712.

It is a tau number, because it is divible by the number of its divisors (56).

It is a junction number, because it is equal to n+sod(n) for n = 21732893 and 21732902.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 62098 + ... + 62446.

It is an arithmetic number, because the mean of its divisors is an integer number (889000).

Almost surely, 2^21732928 is an apocalyptic number.

21732928 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 21732928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24892000).

21732928 is an abundant number, since it is smaller than the sum of its proper divisors (28051072).

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

21732928 is a wasteful number, since it uses less digits than its factorization.

21732928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 507 (or 497 counting only the distinct ones).

The product of its digits is 12096, while the sum is 34.

The square root of 21732928 is about 4661.8588567223. The cubic root of 21732928 is about 279.0654557094.

The spelling of 21732928 in words is "twenty-one million, seven hundred thirty-two thousand, nine hundred twenty-eight".