266585661 has 20 divisors (see below), whose sum is σ = 411968700. Its totient is φ = 171593856.

The previous prime is 266585651. The next prime is 266585699. The reversal of 266585661 is 166585662.

It is a happy number.

266585661 is a `hidden beast` number, since 2 + 6 + 6 + 585 + 6 + 61 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 66928761 + 199656900 = 8181^2 + 14130^2 .

It is not a de Polignac number, because 266585661 - 2¹⁷ = 266454589 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (266585611) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 54396 + ... + 59093.

It is an arithmetic number, because the mean of its divisors is an integer number (20598435).

Almost surely, 2^266585661 is an apocalyptic number.

It is an amenable number.

266585661 is a deficient number, since it is larger than the sum of its proper divisors (145383039).

266585661 is a wasteful number, since it uses less digits than its factorization.

266585661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 113530 (or 113521 counting only the distinct ones).

The product of its digits is 518400, while the sum is 45.

The square root of 266585661 is about 16327.4511482962. The cubic root of 266585661 is about 643.5944080438.

Subtracting from 266585661 its reverse (166585662), we obtain a palindrome (99999999).

The spelling of 266585661 in words is "two hundred sixty-six million, five hundred eighty-five thousand, six hundred sixty-one".