6665 has 8 divisors (see below), whose sum is σ = 8448. Its totient is φ = 5040.

The previous prime is 6661. The next prime is 6673. The reversal of 6665 is 5666.

6665 = T₂₂ + T₂₃ + ... + T₃₆.

It is a happy number.

6665 is nontrivially palindromic in base 6.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 6665 - 2² = 6661 is a prime.

It is a Duffinian number.

6665 is an undulating number in base 6.

It is a Curzon number.

It is a nialpdrome in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 6665.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 6665.

It is not an unprimeable number, because it can be changed into a prime (6661) by changing a digit.

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 in 7 ways as a sum of consecutive naturals, for example, 134 + ... + 176.

It is an arithmetic number, because the mean of its divisors is an integer number (1056).

It is an amenable number.

6665 is a deficient number, since it is larger than the sum of its proper divisors (1783).

6665 is a wasteful number, since it uses less digits than its factorization.

6665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79.

The product of its digits is 1080, while the sum is 23.

The square root of 6665 is about 81.6394512475. The cubic root of 6665 is about 18.8191520535.

Subtracting from 6665 its reverse (5666), we obtain a palindrome (999).

It can be divided in two parts, 66 and 65, that added together give a palindrome (131).

The spelling of 6665 in words is "six thousand, six hundred sixty-five".