91000000891 has 2 divisors, whose sum is σ = 91000000892. Its totient is φ = 91000000890.

The previous prime is 91000000829. The next prime is 91000000921. The reversal of 91000000891 is 19800000019.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91000000891 is a prime.

It is not a weakly prime, because it can be changed into another prime (91000000811) 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, 45500000445 + 45500000446.

It is an arithmetic number, because the mean of its divisors is an integer number (45500000446).

Almost surely, 2^91000000891 is an apocalyptic number.

91000000891 is a deficient number, since it is larger than the sum of its proper divisors (1).

91000000891 is an equidigital number, since it uses as much as digits as its factorization.

91000000891 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 648, while the sum is 28.

The spelling of 91000000891 in words is "ninety-one billion, eight hundred ninety-one", and thus it is an aban number.