266881 has 4 divisors (see below), whose sum is σ = 274132. Its totient is φ = 259632.

The previous prime is 266867. The next prime is 266891. The reversal of 266881 is 188662.

266881 = T₆ + T₇ + ... + T₁₁₆.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 188662 = 2 ⋅94331.

It can be written as a sum of positive squares in 2 ways, for example, as 230400 + 36481 = 480^2 + 191^2 .

It is a cyclic number.

It is not a de Polignac number, because 266881 - 2⁹ = 266369 is a prime.

It is a super-2 number, since 2×266881² = 142450936322, which contains 22 as substring.

It is a Duffinian number.

266881 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (266801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3570 + ... + 3643.

It is an arithmetic number, because the mean of its divisors is an integer number (68533).

2²⁶⁶⁸⁸¹ is an apocalyptic number.

It is an amenable number.

266881 is a deficient number, since it is larger than the sum of its proper divisors (7251).

266881 is an equidigital number, since it uses as much as digits as its factorization.

266881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7250.

The product of its digits is 4608, while the sum is 31.

The square root of 266881 is about 516.6052651687. The cubic root of 266881 is about 64.3831990688.

The spelling of 266881 in words is "two hundred sixty-six thousand, eight hundred eighty-one".