66661010566 has 4 divisors (see below), whose sum is σ = 99991515852. Its totient is φ = 33330505282.

The previous prime is 66661010543. The next prime is 66661010609. The reversal of 66661010566 is 66501016666.

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

It is a congruent 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 as a sum of consecutive naturals, namely, 16665252640 + ... + 16665252643.

It is an arithmetic number, because the mean of its divisors is an integer number (24997878963).

Almost surely, 2^66661010566 is an apocalyptic number.

66661010566 is a deficient number, since it is larger than the sum of its proper divisors (33330505286).

66661010566 is a wasteful number, since it uses less digits than its factorization.

66661010566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33330505285.

The product of its (nonzero) digits is 233280, while the sum is 43.

The spelling of 66661010566 in words is "sixty-six billion, six hundred sixty-one million, ten thousand, five hundred sixty-six".