13815665 has 4 divisors (see below), whose sum is σ = 16578804. Its totient is φ = 11052528.

The previous prime is 13815661. The next prime is 13815667. The reversal of 13815665 is 56651831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 56651831 = 1571 ⋅36061.

It can be written as a sum of positive squares in 2 ways, for example, as 8958049 + 4857616 = 2993^2 + 2204^2 .

It is a cyclic number.

It is not a de Polignac number, because 13815665 - 2² = 13815661 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13815661) 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, 1381562 + ... + 1381571.

It is an arithmetic number, because the mean of its divisors is an integer number (4144701).

Almost surely, 2^13815665 is an apocalyptic number.

It is an amenable number.

13815665 is a deficient number, since it is larger than the sum of its proper divisors (2763139).

13815665 is an equidigital number, since it uses as much as digits as its factorization.

13815665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2763138.

The product of its digits is 21600, while the sum is 35.

The square root of 13815665 is about 3716.9429643189. The cubic root of 13815665 is about 239.9517553488.

The spelling of 13815665 in words is "thirteen million, eight hundred fifteen thousand, six hundred sixty-five".