13665 has 8 divisors (see below), whose sum is σ = 21888. Its totient is φ = 7280.

The previous prime is 13649. The next prime is 13669. The reversal of 13665 is 56631.

13665 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 13665 - 2⁴ = 13649 is a prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 13665.

It is not an unprimeable number, because it can be changed into a prime (13669) 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 7 ways as a sum of consecutive naturals, for example, 441 + ... + 470.

It is an arithmetic number, because the mean of its divisors is an integer number (2736).

2¹³⁶⁶⁵ is an apocalyptic number.

13665 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

13665 is a deficient number, since it is larger than the sum of its proper divisors (8223).

13665 is an equidigital number, since it uses as much as digits as its factorization.

13665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 919.

The product of its digits is 540, while the sum is 21.

The square root of 13665 is about 116.8973909033. The cubic root of 13665 is about 23.9076310664.

The spelling of 13665 in words is "thirteen thousand, six hundred sixty-five".