9990990871 has 2 divisors, whose sum is σ = 9990990872. Its totient is φ = 9990990870.

The previous prime is 9990990857. The next prime is 9990990943. The reversal of 9990990871 is 1780990999.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 9990990871 - 2⁵ = 9990990839 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9990910871) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4995495435 + 4995495436.

It is an arithmetic number, because the mean of its divisors is an integer number (4995495436).

Almost surely, 2^9990990871 is an apocalyptic number.

9990990871 is a deficient number, since it is larger than the sum of its proper divisors (1).

9990990871 is an equidigital number, since it uses as much as digits as its factorization.

9990990871 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3306744, while the sum is 61.

The square root of 9990990871 is about 99954.9442048766. The cubic root of 9990990871 is about 2153.7875096404.

The spelling of 9990990871 in words is "nine billion, nine hundred ninety million, nine hundred ninety thousand, eight hundred seventy-one".