91988645393 has 2 divisors, whose sum is σ = 91988645394. Its totient is φ = 91988645392.

The previous prime is 91988645381. The next prime is 91988645449. The reversal of 91988645393 is 39354688919.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 89596652929 + 2391992464 = 299327^2 + 48908^2 .

It is a cyclic number.

It is not a de Polignac number, because 91988645393 - 2⁸ = 91988645137 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (91988645323) 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 as a sum of consecutive naturals, namely, 45994322696 + 45994322697.

It is an arithmetic number, because the mean of its divisors is an integer number (45994322697).

Almost surely, 2^91988645393 is an apocalyptic number.

It is an amenable number.

91988645393 is a deficient number, since it is larger than the sum of its proper divisors (1).

91988645393 is an equidigital number, since it uses as much as digits as its factorization.

91988645393 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 50388480, while the sum is 65.

The spelling of 91988645393 in words is "ninety-one billion, nine hundred eighty-eight million, six hundred forty-five thousand, three hundred ninety-three".