129999999991871 has 2 divisors, whose sum is σ = 129999999991872. Its totient is φ = 129999999991870.

The previous prime is 129999999991859. The next prime is 129999999991903. The reversal of 129999999991871 is 178199999999921.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 129999999991871 - 2³⁰ = 129998926250047 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (129999999994871) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64999999995935 + 64999999995936.

It is an arithmetic number, because the mean of its divisors is an integer number (64999999995936).

Almost surely, 2^{129999999991871} is an apocalyptic number.

129999999991871 is a deficient number, since it is larger than the sum of its proper divisors (1).

129999999991871 is an equidigital number, since it uses as much as digits as its factorization.

129999999991871 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 43391094768, while the sum is 101.

The spelling of 129999999991871 in words is "one hundred twenty-nine trillion, nine hundred ninety-nine billion, nine hundred ninety-nine million, nine hundred ninety-one thousand, eight hundred seventy-one".