20556065 has 4 divisors (see below), whose sum is σ = 24667284. Its totient is φ = 16444848.

The previous prime is 20556059. The next prime is 20556079. The reversal of 20556065 is 56065502.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 56065502 = 2 ⋅28032751.

It can be written as a sum of positive squares in 2 ways, for example, as 3655744 + 16900321 = 1912^2 + 4111^2 .

It is a cyclic number.

It is not a de Polignac number, because 20556065 - 2⁴ = 20556049 is a prime.

It is a Duffinian number.

It is a Curzon 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 3 ways as a sum of consecutive naturals, for example, 2055602 + ... + 2055611.

It is an arithmetic number, because the mean of its divisors is an integer number (6166821).

Almost surely, 2^20556065 is an apocalyptic number.

It is an amenable number.

20556065 is a deficient number, since it is larger than the sum of its proper divisors (4111219).

20556065 is an equidigital number, since it uses as much as digits as its factorization.

20556065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4111218.

The product of its (nonzero) digits is 9000, while the sum is 29.

The square root of 20556065 is about 4533.8796852144. The cubic root of 20556065 is about 273.9344551693.

The spelling of 20556065 in words is "twenty million, five hundred fifty-six thousand, sixty-five".