8081891789 has 2 divisors, whose sum is σ = 8081891790. Its totient is φ = 8081891788.

The previous prime is 8081891773. The next prime is 8081891821. The reversal of 8081891789 is 9871981808.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7453386889 + 628504900 = 86333^2 + 25070^2 .

It is a cyclic number.

It is not a de Polignac number, because 8081891789 - 2⁴ = 8081891773 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8081891729) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4040945894 + 4040945895.

It is an arithmetic number, because the mean of its divisors is an integer number (4040945895).

Almost surely, 2^8081891789 is an apocalyptic number.

It is an amenable number.

8081891789 is a deficient number, since it is larger than the sum of its proper divisors (1).

8081891789 is an equidigital number, since it uses as much as digits as its factorization.

8081891789 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2322432, while the sum is 59.

The square root of 8081891789 is about 89899.3425393089. The cubic root of 8081891789 is about 2006.8011616341.

The spelling of 8081891789 in words is "eight billion, eighty-one million, eight hundred ninety-one thousand, seven hundred eighty-nine".