266665 has 16 divisors (see below), whose sum is σ = 385920. Its totient is φ = 172800.

The previous prime is 266663. The next prime is 266671. The reversal of 266665 is 566662.

It is not a de Polignac number, because 266665 - 2¹ = 266663 is a prime.

It is a super-2 number, since 2×266665² = 142220444450, which contains 22 as substring.

Its product of digits (12960) is a multiple of the sum of its prime divisors (432).

266665 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (266663) 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 15 ways as a sum of consecutive naturals, for example, 465 + ... + 865.

It is an arithmetic number, because the mean of its divisors is an integer number (24120).

2²⁶⁶⁶⁶⁵ is an apocalyptic number.

It is an amenable number.

266665 is a deficient number, since it is larger than the sum of its proper divisors (119255).

266665 is a wasteful number, since it uses less digits than its factorization.

266665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 432.

The product of its digits is 12960, while the sum is 31.

The square root of 266665 is about 516.3961657487. The cubic root of 266665 is about 64.3658248777.

The spelling of 266665 in words is "two hundred sixty-six thousand, six hundred sixty-five".