6605665657 has 4 divisors (see below), whose sum is σ = 6607188900. Its totient is φ = 6604142416.

The previous prime is 6605665631. The next prime is 6605665669. The reversal of 6605665657 is 7565665066.

6605665657 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.

It can be written as a sum of positive squares in 2 ways, for example, as 2629228176 + 3976437481 = 51276^2 + 63059^2 .

It is a cyclic number.

It is not a de Polignac number, because 6605665657 - 2¹¹ = 6605663609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6605665607) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 755098 + ... + 763795.

It is an arithmetic number, because the mean of its divisors is an integer number (1651797225).

Almost surely, 2^6605665657 is an apocalyptic number.

It is an amenable number.

6605665657 is a deficient number, since it is larger than the sum of its proper divisors (1523243).

6605665657 is a wasteful number, since it uses less digits than its factorization.

6605665657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1523242.

The product of its (nonzero) digits is 6804000, while the sum is 52.

The square root of 6605665657 is about 81275.2462746192. The cubic root of 6605665657 is about 1876.3140448678.

The spelling of 6605665657 in words is "six billion, six hundred five million, six hundred sixty-five thousand, six hundred fifty-seven".