266867681 has 4 divisors (see below), whose sum is σ = 266903700. Its totient is φ = 266831664.

The previous prime is 266867677. The next prime is 266867701. The reversal of 266867681 is 186768662.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 186768662 = 2 ⋅93384331.

It can be written as a sum of positive squares in 2 ways, for example, as 255712081 + 11155600 = 15991^2 + 3340^2 .

It is a cyclic number.

It is not a de Polignac number, because 266867681 - 2² = 266867677 is a prime.

It is a super-2 number, since 2×266867681² = 142436718324635522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (266867621) 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, 2366 + ... + 23223.

It is an arithmetic number, because the mean of its divisors is an integer number (66725925).

Almost surely, 2^266867681 is an apocalyptic number.

It is an amenable number.

266867681 is a deficient number, since it is larger than the sum of its proper divisors (36019).

266867681 is a wasteful number, since it uses less digits than its factorization.

266867681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36018.

The product of its digits is 1161216, while the sum is 50.

The square root of 266867681 is about 16336.0852409627. The cubic root of 266867681 is about 643.8212801204.

The spelling of 266867681 in words is "two hundred sixty-six million, eight hundred sixty-seven thousand, six hundred eighty-one".