266689 has 2 divisors, whose sum is σ = 266690. Its totient is φ = 266688.

The previous prime is 266687. The next prime is 266701. The reversal of 266689 is 986662.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 255025 + 11664 = 505^2 + 108^2 .

It is a cyclic number.

It is not a de Polignac number, because 266689 - 2¹ = 266687 is a prime.

It is a super-2 number, since 2×266689² = 142246045442, which contains 22 as substring.

Together with 266687, it forms a pair of twin primes.

It is a Chen prime.

266689 is a lucky number.

It is a plaindrome in base 10.

It is not a weakly prime, because it can be changed into another prime (266681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 133344 + 133345.

It is an arithmetic number, because the mean of its divisors is an integer number (133345).

2²⁶⁶⁶⁸⁹ is an apocalyptic number.

It is an amenable number.

266689 is a deficient number, since it is larger than the sum of its proper divisors (1).

266689 is an equidigital number, since it uses as much as digits as its factorization.

266689 is an evil number, because the sum of its binary digits is even.

The product of its digits is 31104, while the sum is 37.

The square root of 266689 is about 516.4194031986. The cubic root of 266689 is about 64.3677558066.

The spelling of 266689 in words is "two hundred sixty-six thousand, six hundred eighty-nine".