6661555066 has 4 divisors (see below), whose sum is σ = 9992332602. Its totient is φ = 3330777532.

The previous prime is 6661555057. The next prime is 6661555079. The reversal of 6661555066 is 6605551666.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 6606275841 + 55279225 = 81279^2 + 7435^2 .

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 as a sum of consecutive naturals, namely, 1665388765 + ... + 1665388768.

Almost surely, 2^6661555066 is an apocalyptic number.

6661555066 is a deficient number, since it is larger than the sum of its proper divisors (3330777536).

6661555066 is a wasteful number, since it uses less digits than its factorization.

6661555066 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3330777535.

The product of its (nonzero) digits is 972000, while the sum is 46.

The square root of 6661555066 is about 81618.3500568346. The cubic root of 6661555066 is about 1881.5909147313.

The spelling of 6661555066 in words is "six billion, six hundred sixty-one million, five hundred fifty-five thousand, sixty-six".