9909871 has 2 divisors, whose sum is σ = 9909872. Its totient is φ = 9909870.

The previous prime is 9909869. The next prime is 9909881. The reversal of 9909871 is 1789099.

9909871 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 9909871 - 2¹ = 9909869 is a prime.

Together with 9909869, it forms a pair of twin primes.

9909871 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9909881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4954935 + 4954936.

It is an arithmetic number, because the mean of its divisors is an integer number (4954936).

Almost surely, 2^9909871 is an apocalyptic number.

9909871 is a deficient number, since it is larger than the sum of its proper divisors (1).

9909871 is an equidigital number, since it uses as much as digits as its factorization.

9909871 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40824, while the sum is 43.

The square root of 9909871 is about 3147.9947585725. The cubic root of 9909871 is about 214.7942578400.

The spelling of 9909871 in words is "nine million, nine hundred nine thousand, eight hundred seventy-one".