266405 has 4 divisors (see below), whose sum is σ = 319692. Its totient is φ = 213120.

The previous prime is 266401. The next prime is 266411. The reversal of 266405 is 504662.

266405 is nontrivially palindromic in base 13.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 119716 + 146689 = 346^2 + 383^2 .

It is not a de Polignac number, because 266405 - 2² = 266401 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (266401) 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, 26636 + ... + 26645.

It is an arithmetic number, because the mean of its divisors is an integer number (79923).

2²⁶⁶⁴⁰⁵ is an apocalyptic number.

It is an amenable number.

266405 is a deficient number, since it is larger than the sum of its proper divisors (53287).

266405 is an equidigital number, since it uses as much as digits as its factorization.

266405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53286.

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 266405 is about 516.1443596514. The cubic root of 266405 is about 64.3448990514.

The spelling of 266405 in words is "two hundred sixty-six thousand, four hundred five".