2168891993 has 2 divisors, whose sum is σ = 2168891994. Its totient is φ = 2168891992.

The previous prime is 2168891981. The next prime is 2168892013. The reversal of 2168891993 is 3991988612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1980873049 + 188018944 = 44507^2 + 13712^2 .

It is a cyclic number.

It is not a de Polignac number, because 2168891993 - 2⁶ = 2168891929 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (2168891953) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1084445996 + 1084445997.

It is an arithmetic number, because the mean of its divisors is an integer number (1084445997).

Almost surely, 2^2168891993 is an apocalyptic number.

It is an amenable number.

2168891993 is a deficient number, since it is larger than the sum of its proper divisors (1).

2168891993 is an equidigital number, since it uses as much as digits as its factorization.

2168891993 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1679616, while the sum is 56.

The square root of 2168891993 is about 46571.3645172653. The cubic root of 2168891993 is about 1294.4322020006.

The spelling of 2168891993 in words is "two billion, one hundred sixty-eight million, eight hundred ninety-one thousand, nine hundred ninety-three".