20381728 has 24 divisors (see below), whose sum is σ = 40255488. Its totient is φ = 10158144.

The previous prime is 20381717. The next prime is 20381731. The reversal of 20381728 is 82718302.

It is a self number, because there is not a number n which added to its sum of digits gives 20381728.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11425 + ... + 13087.

It is an arithmetic number, because the mean of its divisors is an integer number (1677312).

Almost surely, 2^20381728 is an apocalyptic number.

It is an amenable number.

20381728 is a deficient number, since it is larger than the sum of its proper divisors (19873760).

20381728 is a wasteful number, since it uses less digits than its factorization.

20381728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2056 (or 2048 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 31.

The square root of 20381728 is about 4514.6127187169. The cubic root of 20381728 is about 273.1578383018.

The spelling of 20381728 in words is "twenty million, three hundred eighty-one thousand, seven hundred twenty-eight".