266491 has 2 divisors, whose sum is σ = 266492. Its totient is φ = 266490.

The previous prime is 266489. The next prime is 266521. The reversal of 266491 is 194662.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 266491 - 2¹ = 266489 is a prime.

Together with 266489, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (266401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 133245 + 133246.

It is an arithmetic number, because the mean of its divisors is an integer number (133246).

2²⁶⁶⁴⁹¹ is an apocalyptic number.

266491 is a deficient number, since it is larger than the sum of its proper divisors (1).

266491 is an equidigital number, since it uses as much as digits as its factorization.

266491 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2592, while the sum is 28.

The square root of 266491 is about 516.2276629550. The cubic root of 266491 is about 64.3518221772.

It can be divided in two parts, 266 and 491, that added together give a palindrome (757).

The spelling of 266491 in words is "two hundred sixty-six thousand, four hundred ninety-one".