2168443891 has 4 divisors (see below), whose sum is σ = 2295999432. Its totient is φ = 2040888352.

The previous prime is 2168443877. The next prime is 2168443909. The reversal of 2168443891 is 1983448612.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 2168443891 - 2²⁵ = 2134889459 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2168443091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 63777745 + ... + 63777778.

It is an arithmetic number, because the mean of its divisors is an integer number (573999858).

Almost surely, 2^2168443891 is an apocalyptic number.

2168443891 is a deficient number, since it is larger than the sum of its proper divisors (127555541).

2168443891 is a wasteful number, since it uses less digits than its factorization.

2168443891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127555540.

The product of its digits is 331776, while the sum is 46.

The square root of 2168443891 is about 46566.5533510910. The cubic root of 2168443891 is about 1294.3430508563.

The spelling of 2168443891 in words is "two billion, one hundred sixty-eight million, four hundred forty-three thousand, eight hundred ninety-one".