20728066 has 16 divisors (see below), whose sum is σ = 33812856. Its totient is φ = 9490176.

The previous prime is 20728063. The next prime is 20728067. The reversal of 20728066 is 66082702.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 20511841 + 216225 = 4529^2 + 465^2 .

It is not an unprimeable number, because it can be changed into a prime (20728061) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6981 + ... + 9496.

Almost surely, 2^20728066 is an apocalyptic number.

20728066 is a deficient number, since it is larger than the sum of its proper divisors (13084790).

20728066 is a wasteful number, since it uses less digits than its factorization.

20728066 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16533.

The product of its (nonzero) digits is 8064, while the sum is 31.

The square root of 20728066 is about 4552.8085837206. The cubic root of 20728066 is about 274.6963745346.

The spelling of 20728066 in words is "twenty million, seven hundred twenty-eight thousand, sixty-six".