166665 has 16 divisors (see below), whose sum is σ = 274176. Its totient is φ = 86400.

The previous prime is 166657. The next prime is 166667. The reversal of 166665 is 566661.

It is not a de Polignac number, because 166665 - 2³ = 166657 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166667) 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, 480 + ... + 750.

It is an arithmetic number, because the mean of its divisors is an integer number (17136).

2¹⁶⁶⁶⁶⁵ is an apocalyptic number.

166665 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

166665 is a deficient number, since it is larger than the sum of its proper divisors (107511).

166665 is a wasteful number, since it uses less digits than its factorization.

166665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 320.

The product of its digits is 6480, while the sum is 30.

The square root of 166665 is about 408.2462492173. The cubic root of 166665 is about 55.0319373739.

It can be divided in two parts, 1 and 66665, that added together give a palindrome (66666).

The spelling of 166665 in words is "one hundred sixty-six thousand, six hundred sixty-five".