6660216999871 has 2 divisors, whose sum is σ = 6660216999872. Its totient is φ = 6660216999870.

The previous prime is 6660216999851. The next prime is 6660216999907. The reversal of 6660216999871 is 1789996120666.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 6660216999871 - 2⁷ = 6660216999743 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 6660216999871.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6660216999851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3330108499935 + 3330108499936.

It is an arithmetic number, because the mean of its divisors is an integer number (3330108499936).

Almost surely, 2^{6660216999871} is an apocalyptic number.

6660216999871 is a deficient number, since it is larger than the sum of its proper divisors (1).

6660216999871 is an equidigital number, since it uses as much as digits as its factorization.

6660216999871 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 105815808, while the sum is 70.

The spelling of 6660216999871 in words is "six trillion, six hundred sixty billion, two hundred sixteen million, nine hundred ninety-nine thousand, eight hundred seventy-one".