20565071 has 4 divisors (see below), whose sum is σ = 20609952. Its totient is φ = 20520192.

The previous prime is 20565001. The next prime is 20565073. The reversal of 20565071 is 17056502.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20565071 - 2¹⁸ = 20302927 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20565071.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20565073) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21746 + ... + 22671.

It is an arithmetic number, because the mean of its divisors is an integer number (5152488).

Almost surely, 2^20565071 is an apocalyptic number.

20565071 is a deficient number, since it is larger than the sum of its proper divisors (44881).

20565071 is an equidigital number, since it uses as much as digits as its factorization.

20565071 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44880.

The product of its (nonzero) digits is 2100, while the sum is 26.

The square root of 20565071 is about 4534.8727655801. The cubic root of 20565071 is about 273.9744546131.

The spelling of 20565071 in words is "twenty million, five hundred sixty-five thousand, seventy-one".