8999999999891 has 2 divisors, whose sum is σ = 8999999999892. Its totient is φ = 8999999999890.

The previous prime is 8999999999867. The next prime is 8999999999911. The reversal of 8999999999891 is 1989999999998.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 8999999999891 - 2⁶ = 8999999999827 is a prime.

It is not a weakly prime, because it can be changed into another prime (8999999999801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4499999999945 + 4499999999946.

It is an arithmetic number, because the mean of its divisors is an integer number (4499999999946).

Almost surely, 2^{8999999999891} is an apocalyptic number.

8999999999891 is a deficient number, since it is larger than the sum of its proper divisors (1).

8999999999891 is an equidigital number, since it uses as much as digits as its factorization.

8999999999891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 223154201664, while the sum is 107.

Adding to 8999999999891 its sum of digits (107), we get a palindrome (8999999999998).

It can be divided in two parts, 89999999998 and 91, that multiplied together give a palindrome (8189999999818).

The spelling of 8999999999891 in words is "eight trillion, nine hundred ninety-nine billion, nine hundred ninety-nine million, nine hundred ninety-nine thousand, eight hundred ninety-one".