9988886861 has 2 divisors, whose sum is σ = 9988886862. Its totient is φ = 9988886860.

The previous prime is 9988886857. The next prime is 9988886863. The reversal of 9988886861 is 1686888899.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9966028900 + 22857961 = 99830^2 + 4781^2 .

It is a cyclic number.

It is not a de Polignac number, because 9988886861 - 2² = 9988886857 is a prime.

It is a Sophie Germain prime.

Together with 9988886863, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9988886863) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4994443430 + 4994443431.

It is an arithmetic number, because the mean of its divisors is an integer number (4994443431).

Almost surely, 2^9988886861 is an apocalyptic number.

It is an amenable number.

9988886861 is a deficient number, since it is larger than the sum of its proper divisors (1).

9988886861 is an equidigital number, since it uses as much as digits as its factorization.

9988886861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 95551488, while the sum is 71.

The square root of 9988886861 is about 99944.4188586836. The cubic root of 9988886861 is about 2153.6363098026.

The spelling of 9988886861 in words is "nine billion, nine hundred eighty-eight million, eight hundred eighty-six thousand, eight hundred sixty-one".