20728816 has 10 divisors (see below), whose sum is σ = 40162112. Its totient is φ = 10364400.

The previous prime is 20728811. The next prime is 20728817. The reversal of 20728816 is 61882702.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20728811) 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 as a sum of consecutive naturals, namely, 647760 + ... + 647791.

Almost surely, 2^20728816 is an apocalyptic number.

It is an amenable number.

20728816 is a deficient number, since it is larger than the sum of its proper divisors (19433296).

20728816 is a wasteful number, since it uses less digits than its factorization.

20728816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1295559 (or 1295553 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 34.

The square root of 20728816 is about 4552.8909497154. The cubic root of 20728816 is about 274.6996875917.

The spelling of 20728816 in words is "twenty million, seven hundred twenty-eight thousand, eight hundred sixteen".