12820645666 has 16 divisors (see below), whose sum is σ = 19478874240. Its totient is φ = 6327725040.

The previous prime is 12820645631. The next prime is 12820645703. The reversal of 12820645666 is 66654602821.

12820645666 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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, 1087021 + ... + 1098751.

It is an arithmetic number, because the mean of its divisors is an integer number (1217429640).

Almost surely, 2^12820645666 is an apocalyptic number.

12820645666 is a deficient number, since it is larger than the sum of its proper divisors (6658228574).

12820645666 is a wasteful number, since it uses less digits than its factorization.

12820645666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18729.

The product of its (nonzero) digits is 829440, while the sum is 46.

The spelling of 12820645666 in words is "twelve billion, eight hundred twenty million, six hundred forty-five thousand, six hundred sixty-six".