9999999999971 has 2 divisors, whose sum is σ = 9999999999972. Its totient is φ = 9999999999970.

The previous prime is 9999999999863. The next prime is 10000000000037. The reversal of 9999999999971 is 1799999999999.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9999999999971 is a prime.

It is a super-9 number, since 9×9999999999971⁹ (a number of 118 digits) contains 999999999 as substring.

It is a nialpdrome in base 10.

It is not a weakly prime, because it can be changed into another prime (9999999996971) 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, 4999999999985 + 4999999999986.

It is an arithmetic number, because the mean of its divisors is an integer number (4999999999986).

Almost surely, 2^{9999999999971} is an apocalyptic number.

9999999999971 is a deficient number, since it is larger than the sum of its proper divisors (1).

9999999999971 is an equidigital number, since it uses as much as digits as its factorization.

9999999999971 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 219667417263, while the sum is 107.

The spelling of 9999999999971 in words is "nine trillion, nine hundred ninety-nine billion, nine hundred ninety-nine million, nine hundred ninety-nine thousand, nine hundred seventy-one".