21928512 has 56 divisors (see below), whose sum is σ = 58432192. Its totient is φ = 7257600.

The previous prime is 21928493. The next prime is 21928523. The reversal of 21928512 is 21582912.

It is a self number, because there is not a number n which added to its sum of digits gives 21928512.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 34437 + ... + 35067.

It is an arithmetic number, because the mean of its divisors is an integer number (1043432).

Almost surely, 2^21928512 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 21928512, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29216096).

21928512 is an abundant number, since it is smaller than the sum of its proper divisors (36503680).

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

21928512 is a wasteful number, since it uses less digits than its factorization.

21928512 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 827 (or 817 counting only the distinct ones).

The product of its digits is 2880, while the sum is 30.

The square root of 21928512 is about 4682.7889126033. The cubic root of 21928512 is about 279.9001004161.

The spelling of 21928512 in words is "twenty-one million, nine hundred twenty-eight thousand, five hundred twelve".