21272928 has 96 divisors (see below), whose sum is σ = 58949856. Its totient is φ = 6709248.

The previous prime is 21272843. The next prime is 21272947. The reversal of 21272928 is 82927212.

It is a tau number, because it is divible by the number of its divisors (96).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 188200 + ... + 188312.

It is an arithmetic number, because the mean of its divisors is an integer number (614061).

Almost surely, 2^21272928 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 21272928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29474928).

21272928 is an abundant number, since it is smaller than the sum of its proper divisors (37676928).

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

21272928 is a wasteful number, since it uses less digits than its factorization.

21272928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 216 (or 208 counting only the distinct ones).

The product of its digits is 8064, while the sum is 33.

The square root of 21272928 is about 4612.2584489597. The cubic root of 21272928 is about 277.0824952933.

The spelling of 21272928 in words is "twenty-one million, two hundred seventy-two thousand, nine hundred twenty-eight".