266191 has 8 divisors (see below), whose sum is σ = 281520. Its totient is φ = 251328.

The previous prime is 266183. The next prime is 266221. The reversal of 266191 is 191662.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 266191 - 2³ = 266183 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (266111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1875 + ... + 2011.

It is an arithmetic number, because the mean of its divisors is an integer number (35190).

2²⁶⁶¹⁹¹ is an apocalyptic number.

266191 is a deficient number, since it is larger than the sum of its proper divisors (15329).

266191 is a wasteful number, since it uses less digits than its factorization.

266191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 233.

The product of its digits is 648, while the sum is 25.

The square root of 266191 is about 515.9370116594. The cubic root of 266191 is about 64.3276652694.

Subtracting from 266191 its reverse (191662), we obtain a square (74529 = 273²).

The spelling of 266191 in words is "two hundred sixty-six thousand, one hundred ninety-one".