16668316891 has 2 divisors, whose sum is σ = 16668316892. Its totient is φ = 16668316890.

The previous prime is 16668316849. The next prime is 16668316963. The reversal of 16668316891 is 19861386661.

It is a happy number.

16668316891 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is an emirp because it is prime and its reverse (19861386661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 16668316891 - 2¹⁵ = 16668284123 is a prime.

It is not a weakly prime, because it can be changed into another prime (16668376891) by changing a digit.

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, 8334158445 + 8334158446.

It is an arithmetic number, because the mean of its divisors is an integer number (8334158446).

Almost surely, 2^16668316891 is an apocalyptic number.

16668316891 is a deficient number, since it is larger than the sum of its proper divisors (1).

16668316891 is an equidigital number, since it uses as much as digits as its factorization.

16668316891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2239488, while the sum is 55.

The spelling of 16668316891 in words is "sixteen billion, six hundred sixty-eight million, three hundred sixteen thousand, eight hundred ninety-one".