91321808849 has 2 divisors, whose sum is σ = 91321808850. Its totient is φ = 91321808848.

The previous prime is 91321808807. The next prime is 91321808857. The reversal of 91321808849 is 94880812319.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 52931284624 + 38390524225 = 230068^2 + 195935^2 .

It is a cyclic number.

It is not a de Polignac number, because 91321808849 - 2³² = 87026841553 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 91321808849.

It is not a weakly prime, because it can be changed into another prime (91321888849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45660904424 + 45660904425.

It is an arithmetic number, because the mean of its divisors is an integer number (45660904425).

Almost surely, 2^91321808849 is an apocalyptic number.

It is an amenable number.

91321808849 is a deficient number, since it is larger than the sum of its proper divisors (1).

91321808849 is an equidigital number, since it uses as much as digits as its factorization.

91321808849 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 995328, while the sum is 53.

The spelling of 91321808849 in words is "ninety-one billion, three hundred twenty-one million, eight hundred eight thousand, eight hundred forty-nine".