20553565 has 4 divisors (see below), whose sum is σ = 24664284. Its totient is φ = 16442848.

The previous prime is 20553557. The next prime is 20553569. The reversal of 20553565 is 56535502.

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

It can be written as a sum of positive squares in 2 ways, for example, as 7722841 + 12830724 = 2779^2 + 3582^2 .

It is a cyclic number.

It is not a de Polignac number, because 20553565 - 2³ = 20553557 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20553569) 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, 2055352 + ... + 2055361.

It is an arithmetic number, because the mean of its divisors is an integer number (6166071).

Almost surely, 2^20553565 is an apocalyptic number.

It is an amenable number.

20553565 is a deficient number, since it is larger than the sum of its proper divisors (4110719).

20553565 is an equidigital number, since it uses as much as digits as its factorization.

20553565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4110718.

The product of its (nonzero) digits is 22500, while the sum is 31.

The square root of 20553565 is about 4533.6039747644. The cubic root of 20553565 is about 273.9233495434.

The spelling of 20553565 in words is "twenty million, five hundred fifty-three thousand, five hundred sixty-five".