21928716 has 72 divisors (see below), whose sum is σ = 57845424. Its totient is φ = 6998400.

The previous prime is 21928663. The next prime is 21928721. The reversal of 21928716 is 61782912.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 134451 + ... + 134613.

Almost surely, 2^21928716 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 21928716, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28922712).

21928716 is an abundant number, since it is smaller than the sum of its proper divisors (35916708).

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

21928716 is a wasteful number, since it uses less digits than its factorization.

21928716 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 311 (or 306 counting only the distinct ones).

The product of its digits is 12096, while the sum is 36.

The square root of 21928716 is about 4682.8106944441. The cubic root of 21928716 is about 279.9009683796.

The spelling of 21928716 in words is "twenty-one million, nine hundred twenty-eight thousand, seven hundred sixteen".