13665865 has 4 divisors (see below), whose sum is σ = 16399044. Its totient is φ = 10932688.

The previous prime is 13665863. The next prime is 13665871. The reversal of 13665865 is 56856631.

13665865 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 56856631 = 13 ⋅4373587.

It can be written as a sum of positive squares in 2 ways, for example, as 6568969 + 7096896 = 2563^2 + 2664^2 .

It is a cyclic number.

It is not a de Polignac number, because 13665865 - 2¹ = 13665863 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13665863) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1366582 + ... + 1366591.

It is an arithmetic number, because the mean of its divisors is an integer number (4099761).

Almost surely, 2^13665865 is an apocalyptic number.

It is an amenable number.

13665865 is a deficient number, since it is larger than the sum of its proper divisors (2733179).

13665865 is an equidigital number, since it uses as much as digits as its factorization.

13665865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2733178.

The product of its digits is 129600, while the sum is 40.

The square root of 13665865 is about 3696.7370747728. The cubic root of 13665865 is about 239.0813550993.

The spelling of 13665865 in words is "thirteen million, six hundred sixty-five thousand, eight hundred sixty-five".