266020564561 has 4 divisors (see below), whose sum is σ = 267055664292. Its totient is φ = 264985464832.

The previous prime is 266020564531. The next prime is 266020564583. The reversal of 266020564561 is 165465020662.

It is a happy number.

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 162493641025 + 103526923536 = 403105^2 + 321756^2 .

It is a cyclic number.

It is not a de Polignac number, because 266020564561 - 2⁹ = 266020564049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (266020564501) 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, 517549480 + ... + 517549993.

It is an arithmetic number, because the mean of its divisors is an integer number (66763916073).

Almost surely, 2^266020564561 is an apocalyptic number.

It is an amenable number.

266020564561 is a deficient number, since it is larger than the sum of its proper divisors (1035099731).

266020564561 is a wasteful number, since it uses less digits than its factorization.

266020564561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1035099730.

The product of its (nonzero) digits is 518400, while the sum is 43.

The spelling of 266020564561 in words is "two hundred sixty-six billion, twenty million, five hundred sixty-four thousand, five hundred sixty-one".