6815665 has 4 divisors (see below), whose sum is σ = 8178804. Its totient is φ = 5452528.

The previous prime is 6815651. The next prime is 6815671. The reversal of 6815665 is 5665186.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5665186 = 2 ⋅2832593.

It can be written as a sum of positive squares in 2 ways, for example, as 4309776 + 2505889 = 2076^2 + 1583^2 .

It is a cyclic number.

It is not a de Polignac number, because 6815665 - 2¹³ = 6807473 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 681562 + ... + 681571.

It is an arithmetic number, because the mean of its divisors is an integer number (2044701).

Almost surely, 2^6815665 is an apocalyptic number.

It is an amenable number.

6815665 is a deficient number, since it is larger than the sum of its proper divisors (1363139).

6815665 is a wasteful number, since it uses less digits than its factorization.

6815665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1363138.

The product of its digits is 43200, while the sum is 37.

The square root of 6815665 is about 2610.6828608623. The cubic root of 6815665 is about 189.5990158370.

The spelling of 6815665 in words is "six million, eight hundred fifteen thousand, six hundred sixty-five".