9987948497861 has 2 divisors, whose sum is σ = 9987948497862. Its totient is φ = 9987948497860.

The previous prime is 9987948497809. The next prime is 9987948497957. The reversal of 9987948497861 is 1687948497899.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9553971902500 + 433976595361 = 3090950^2 + 658769^2 .

It is a cyclic number.

It is not a de Polignac number, because 9987948497861 - 2¹⁰ = 9987948496837 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9987948496861) 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, 4993974248930 + 4993974248931.

It is an arithmetic number, because the mean of its divisors is an integer number (4993974248931).

Almost surely, 2^{9987948497861} is an apocalyptic number.

It is an amenable number.

9987948497861 is a deficient number, since it is larger than the sum of its proper divisors (1).

9987948497861 is an equidigital number, since it uses as much as digits as its factorization.

9987948497861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15801827328, while the sum is 89.

The spelling of 9987948497861 in words is "nine trillion, nine hundred eighty-seven billion, nine hundred forty-eight million, four hundred ninety-seven thousand, eight hundred sixty-one".