6646623566 has 16 divisors (see below), whose sum is σ = 11007335808. Its totient is φ = 2984791800.

The previous prime is 6646623551. The next prime is 6646623589. The reversal of 6646623566 is 6653266466.

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 in 7 ways as a sum of consecutive naturals, for example, 1818170 + ... + 1821821.

It is an arithmetic number, because the mean of its divisors is an integer number (687958488).

Almost surely, 2^6646623566 is an apocalyptic number.

6646623566 is a deficient number, since it is larger than the sum of its proper divisors (4360712242).

6646623566 is a wasteful number, since it uses less digits than its factorization.

6646623566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3640087.

The product of its digits is 5598720, while the sum is 50.

The square root of 6646623566 is about 81526.8272778967. The cubic root of 6646623566 is about 1880.1840364202.

The spelling of 6646623566 in words is "six billion, six hundred forty-six million, six hundred twenty-three thousand, five hundred sixty-six".