991047568837 has 2 divisors, whose sum is σ = 991047568838. Its totient is φ = 991047568836.

The previous prime is 991047568811. The next prime is 991047568913. The reversal of 991047568837 is 738865740199.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 808931152836 + 182116416001 = 899406^2 + 426751^2 .

It is a cyclic number.

It is not a de Polignac number, because 991047568837 - 2¹⁹ = 991047044549 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (991047568807) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495523784418 + 495523784419.

It is an arithmetic number, because the mean of its divisors is an integer number (495523784419).

Almost surely, 2^991047568837 is an apocalyptic number.

It is an amenable number.

991047568837 is a deficient number, since it is larger than the sum of its proper divisors (1).

991047568837 is an equidigital number, since it uses as much as digits as its factorization.

991047568837 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 91445760, while the sum is 67.

The spelling of 991047568837 in words is "nine hundred ninety-one billion, forty-seven million, five hundred sixty-eight thousand, eight hundred thirty-seven".