6661555065 has 48 divisors (see below), whose sum is σ = 12784464576. Its totient is φ = 3181622400.

The previous prime is 6661555057. The next prime is 6661555079. The reversal of 6661555065 is 5605551666.

It is not a de Polignac number, because 6661555065 - 2³ = 6661555057 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 6661555065.

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 47 ways as a sum of consecutive naturals, for example, 67266 + ... + 133595.

It is an arithmetic number, because the mean of its divisors is an integer number (266343012).

Almost surely, 2^6661555065 is an apocalyptic number.

It is an amenable number.

6661555065 is a deficient number, since it is larger than the sum of its proper divisors (6122909511).

6661555065 is a wasteful number, since it uses less digits than its factorization.

6661555065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 200950 (or 200947 counting only the distinct ones).

The product of its (nonzero) digits is 810000, while the sum is 45.

The square root of 6661555065 is about 81618.3500507086. The cubic root of 6661555065 is about 1881.5909146371.

The spelling of 6661555065 in words is "six billion, six hundred sixty-one million, five hundred fifty-five thousand, sixty-five".