266020664561 has 4 divisors (see below), whose sum is σ = 270381659124. Its totient is φ = 261659670000.

The previous prime is 266020664461. The next prime is 266020664563. The reversal of 266020664561 is 165466020662.

It is a happy number.

266020664561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 93563186161 + 172457478400 = 305881^2 + 415280^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-266020664561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (266020664563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2180497190 + ... + 2180497311.

It is an arithmetic number, because the mean of its divisors is an integer number (67595414781).

Almost surely, 2^266020664561 is an apocalyptic number.

It is an amenable number.

266020664561 is a deficient number, since it is larger than the sum of its proper divisors (4360994563).

266020664561 is an equidigital number, since it uses as much as digits as its factorization.

266020664561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4360994562.

The product of its (nonzero) digits is 622080, while the sum is 44.

The spelling of 266020664561 in words is "two hundred sixty-six billion, twenty million, six hundred sixty-four thousand, five hundred sixty-one".