266391 has 6 divisors (see below), whose sum is σ = 384800. Its totient is φ = 177588.

The previous prime is 266381. The next prime is 266401. The reversal of 266391 is 193662.

It is a happy number.

266391 is a `hidden beast` number, since 26 + 639 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (266381) and next prime (266401).

It is not a de Polignac number, because 266391 - 2⁵ = 266359 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 (266351) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 14791 + ... + 14808.

2²⁶⁶³⁹¹ is an apocalyptic number.

266391 is a deficient number, since it is larger than the sum of its proper divisors (118409).

266391 is a wasteful number, since it uses less digits than its factorization.

266391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29605 (or 29602 counting only the distinct ones).

The product of its digits is 1944, while the sum is 27.

The square root of 266391 is about 516.1307973760. The cubic root of 266391 is about 64.3437718900.

The spelling of 266391 in words is "two hundred sixty-six thousand, three hundred ninety-one".