20728765 has 16 divisors (see below), whose sum is σ = 26179200. Its totient is φ = 15733312.

The previous prime is 20728759. The next prime is 20728781. The reversal of 20728765 is 56782702.

It is not a de Polignac number, because 20728765 - 2⁵ = 20728733 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7344 + ... + 9766.

It is an arithmetic number, because the mean of its divisors is an integer number (1636200).

Almost surely, 2^20728765 is an apocalyptic number.

It is an amenable number.

20728765 is a deficient number, since it is larger than the sum of its proper divisors (5450435).

20728765 is a wasteful number, since it uses less digits than its factorization.

20728765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2516.

The product of its (nonzero) digits is 47040, while the sum is 37.

The square root of 20728765 is about 4552.8853488749. The cubic root of 20728765 is about 274.6994623063.

The spelling of 20728765 in words is "twenty million, seven hundred twenty-eight thousand, seven hundred sixty-five".