19889728 has 56 divisors (see below), whose sum is σ = 42437304. Its totient is φ = 9216000.

The previous prime is 19889717. The next prime is 19889731. The reversal of 19889728 is 82798891.

It can be written as a sum of positive squares in 4 ways, for example, as 4460544 + 15429184 = 2112^2 + 3928^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 109798 + ... + 109978.

It is an arithmetic number, because the mean of its divisors is an integer number (757809).

Almost surely, 2^19889728 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 19889728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21218652).

19889728 is an abundant number, since it is smaller than the sum of its proper divisors (22547576).

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

19889728 is a wasteful number, since it uses less digits than its factorization.

19889728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 311 (or 301 counting only the distinct ones).

The product of its digits is 580608, while the sum is 52.

The square root of 19889728 is about 4459.7901295913. The cubic root of 19889728 is about 270.9419682115.

The spelling of 19889728 in words is "nineteen million, eight hundred eighty-nine thousand, seven hundred twenty-eight".