21928704 has 72 divisors (see below), whose sum is σ = 66716160. Its totient is φ = 6263808.

The previous prime is 21928663. The next prime is 21928721. The reversal of 21928704 is 40782912.

It is a happy number.

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, 3337 + ... + 7415.

Almost surely, 2^21928704 is an apocalyptic number.

21928704 is a gapful number since it is divisible by the number (24) 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 21928704, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33358080).

21928704 is an abundant number, since it is smaller than the sum of its proper divisors (44787456).

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

21928704 is an equidigital number, since it uses as much as digits as its factorization.

21928704 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4105 (or 4091 counting only the distinct ones).

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

The square root of 21928704 is about 4682.8094131621. The cubic root of 21928704 is about 279.9009173230.

The spelling of 21928704 in words is "twenty-one million, nine hundred twenty-eight thousand, seven hundred four".