20728516 has 12 divisors (see below), whose sum is σ = 36349740. Its totient is φ = 10342880.

The previous prime is 20728501. The next prime is 20728517. The reversal of 20728516 is 61582702.

It can be written as a sum of positive squares in 2 ways, for example, as 14745600 + 5982916 = 3840^2 + 2446^2 .

It is not an unprimeable number, because it can be changed into a prime (20728517) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 3055 + ... + 7126.

It is an arithmetic number, because the mean of its divisors is an integer number (3029145).

Almost surely, 2^20728516 is an apocalyptic number.

It is an amenable number.

20728516 is a deficient number, since it is larger than the sum of its proper divisors (15621224).

20728516 is a wasteful number, since it uses less digits than its factorization.

20728516 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10694 (or 10692 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 31.

The square root of 20728516 is about 4552.8580034963. The cubic root of 20728516 is about 274.6983623784.

The spelling of 20728516 in words is "twenty million, seven hundred twenty-eight thousand, five hundred sixteen".