20873565 has 16 divisors (see below), whose sum is σ = 37108800. Its totient is φ = 11132496.

The previous prime is 20873563. The next prime is 20873599. The reversal of 20873565 is 56537802.

20873565 is a `hidden beast` number, since 20 + 8 + 73 + 565 = 666.

It is not a de Polignac number, because 20873565 - 2¹ = 20873563 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20873563) 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, 77175 + ... + 77444.

It is an arithmetic number, because the mean of its divisors is an integer number (2319300).

Almost surely, 2^20873565 is an apocalyptic number.

It is an amenable number.

20873565 is a deficient number, since it is larger than the sum of its proper divisors (16235235).

20873565 is a wasteful number, since it uses less digits than its factorization.

20873565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154633 (or 154627 counting only the distinct ones).

The product of its (nonzero) digits is 50400, while the sum is 36.

The square root of 20873565 is about 4568.7596785123. The cubic root of 20873565 is about 275.3376128969.

The spelling of 20873565 in words is "twenty million, eight hundred seventy-three thousand, five hundred sixty-five".