6666656566 has 16 divisors (see below), whose sum is σ = 10080007200. Its totient is φ = 3306751488.

The previous prime is 6666656543. The next prime is 6666656611. The reversal of 6666656566 is 6656566666.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 6666656566.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 114520 + ... + 162628.

It is an arithmetic number, because the mean of its divisors is an integer number (630000450).

Almost surely, 2^6666656566 is an apocalyptic number.

6666656566 is a deficient number, since it is larger than the sum of its proper divisors (3413350634).

6666656566 is a wasteful number, since it uses less digits than its factorization.

6666656566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48663.

The product of its digits is 41990400, while the sum is 58.

The square root of 6666656566 is about 81649.5962390507. The cubic root of 6666656566 is about 1882.0711072525.

The spelling of 6666656566 in words is "six billion, six hundred sixty-six million, six hundred fifty-six thousand, five hundred sixty-six".