20500565 has 8 divisors (see below), whose sum is σ = 24634368. Its totient is φ = 16378000.

The previous prime is 20500541. The next prime is 20500577. The reversal of 20500565 is 56500502.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20500565 - 2²⁰ = 19451989 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 20500565.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 1940 + ... + 6690.

It is an arithmetic number, because the mean of its divisors is an integer number (3079296).

Almost surely, 2^20500565 is an apocalyptic number.

It is an amenable number.

20500565 is a deficient number, since it is larger than the sum of its proper divisors (4133803).

20500565 is an equidigital number, since it uses as much as digits as its factorization.

20500565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5619.

The product of its (nonzero) digits is 1500, while the sum is 23.

The square root of 20500565 is about 4527.7549624510. The cubic root of 20500565 is about 273.6876980604.

The spelling of 20500565 in words is "twenty million, five hundred thousand, five hundred sixty-five".