266006665220561 has 4 divisors (see below), whose sum is σ = 266023476628992. Its totient is φ = 265989853812132.

The previous prime is 266006665220479. The next prime is 266006665220563. The reversal of 266006665220561 is 165022566600662.

266006665220561 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, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 266006665220561 - 2¹⁴ = 266006665204177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (266006665220563) 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, 8405680481 + ... + 8405712126.

It is an arithmetic number, because the mean of its divisors is an integer number (66505869157248).

Almost surely, 2^{266006665220561} is an apocalyptic number.

It is an amenable number.

266006665220561 is a deficient number, since it is larger than the sum of its proper divisors (16811408431).

266006665220561 is a wasteful number, since it uses less digits than its factorization.

266006665220561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16811408430.

The product of its (nonzero) digits is 9331200, while the sum is 53.

The spelling of 266006665220561 in words is "two hundred sixty-six trillion, six billion, six hundred sixty-five million, two hundred twenty thousand, five hundred sixty-one".