20728506 has 32 divisors (see below), whose sum is σ = 43848000. Its totient is φ = 6514560.

The previous prime is 20728501. The next prime is 20728517. The reversal of 20728506 is 60582702.

It is not an unprimeable number, because it can be changed into a prime (20728501) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 39526 + ... + 40046.

It is an arithmetic number, because the mean of its divisors is an integer number (1370250).

Almost surely, 2^20728506 is an apocalyptic number.

20728506 is an abundant number, since it is smaller than the sum of its proper divisors (23119494).

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

20728506 is a wasteful number, since it uses less digits than its factorization.

20728506 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 894.

The product of its (nonzero) digits is 6720, while the sum is 30.

The square root of 20728506 is about 4552.8569052849. The cubic root of 20728506 is about 274.6983182044.

The spelling of 20728506 in words is "twenty million, seven hundred twenty-eight thousand, five hundred six".