266442721 has 4 divisors (see below), whose sum is σ = 266502852. Its totient is φ = 266382592.

The previous prime is 266442707. The next prime is 266442763. The reversal of 266442721 is 127244662.

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 137733696 + 128709025 = 11736^2 + 11345^2 .

It is a cyclic number.

It is not a de Polignac number, because 266442721 - 2²³ = 258054113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (266442821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22840 + ... + 32473.

It is an arithmetic number, because the mean of its divisors is an integer number (66625713).

Almost surely, 2^266442721 is an apocalyptic number.

It is an amenable number.

266442721 is a deficient number, since it is larger than the sum of its proper divisors (60131).

266442721 is an equidigital number, since it uses as much as digits as its factorization.

266442721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60130.

The product of its digits is 32256, while the sum is 34.

The square root of 266442721 is about 16323.0732706804. The cubic root of 266442721 is about 643.4793583052.

The spelling of 266442721 in words is "two hundred sixty-six million, four hundred forty-two thousand, seven hundred twenty-one".