13663865 has 8 divisors (see below), whose sum is σ = 16796808. Its totient is φ = 10664320.

The previous prime is 13663861. The next prime is 13663873. The reversal of 13663865 is 56836631.

It can be written as a sum of positive squares in 4 ways, for example, as 1420864 + 12243001 = 1192^2 + 3499^2 .

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

It is not a de Polignac number, because 13663865 - 2² = 13663861 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (13663861) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 33122 + ... + 33531.

It is an arithmetic number, because the mean of its divisors is an integer number (2099601).

Almost surely, 2^13663865 is an apocalyptic number.

It is an amenable number.

13663865 is a deficient number, since it is larger than the sum of its proper divisors (3132943).

13663865 is an equidigital number, since it uses as much as digits as its factorization.

13663865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66699.

The product of its digits is 77760, while the sum is 38.

The square root of 13663865 is about 3696.4665560505. The cubic root of 13663865 is about 239.0696913411.

The spelling of 13663865 in words is "thirteen million, six hundred sixty-three thousand, eight hundred sixty-five".