266506 has 4 divisors (see below), whose sum is σ = 399762. Its totient is φ = 133252.

The previous prime is 266491. The next prime is 266521. The reversal of 266506 is 605662.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 605662 = 2 ⋅302831.

It is an interprime number because it is at equal distance from previous prime (266491) and next prime (266521).

It can be written as a sum of positive squares in only one way, i.e., 167281 + 99225 = 409^2 + 315^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 66625 + ... + 66628.

2²⁶⁶⁵⁰⁶ is an apocalyptic number.

266506 is the 327-th centered pentagonal number.

266506 is a deficient number, since it is larger than the sum of its proper divisors (133256).

266506 is a wasteful number, since it uses less digits than its factorization.

266506 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133255.

The product of its (nonzero) digits is 2160, while the sum is 25.

The square root of 266506 is about 516.2421912242. The cubic root of 266506 is about 64.3530295466.

The spelling of 266506 in words is "two hundred sixty-six thousand, five hundred six".