20109728 has 48 divisors (see below), whose sum is σ = 41912640. Its totient is φ = 9478656.

The previous prime is 20109709. The next prime is 20109743. The reversal of 20109728 is 82790102.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 20109728.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 65351 + ... + 65657.

It is an arithmetic number, because the mean of its divisors is an integer number (873180).

Almost surely, 2^20109728 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 20109728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20956320).

20109728 is an abundant number, since it is smaller than the sum of its proper divisors (21802912).

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

20109728 is a wasteful number, since it uses less digits than its factorization.

20109728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 429 (or 421 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 29.

The square root of 20109728 is about 4484.3871376142. The cubic root of 20109728 is about 271.9372692707.

The spelling of 20109728 in words is "twenty million, one hundred nine thousand, seven hundred twenty-eight".