266135561 has 8 divisors (see below), whose sum is σ = 289407240. Its totient is φ = 243710208.

The previous prime is 266135549. The next prime is 266135563. The reversal of 266135561 is 165531662.

It can be written as a sum of positive squares in 4 ways, for example, as 51337225 + 214798336 = 7165^2 + 14656^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 266135561 - 2¹⁸ = 265873417 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (266135563) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 210926 + ... + 212183.

It is an arithmetic number, because the mean of its divisors is an integer number (36175905).

Almost surely, 2^266135561 is an apocalyptic number.

It is an amenable number.

266135561 is a deficient number, since it is larger than the sum of its proper divisors (23271679).

266135561 is a wasteful number, since it uses less digits than its factorization.

266135561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 423163.

The product of its digits is 32400, while the sum is 35.

The square root of 266135561 is about 16313.6617900458. The cubic root of 266135561 is about 643.2319916672.

The spelling of 266135561 in words is "two hundred sixty-six million, one hundred thirty-five thousand, five hundred sixty-one".