129131871 has 16 divisors (see below), whose sum is σ = 188922240. Its totient is φ = 77805920.

The previous prime is 129131869. The next prime is 129131879. The reversal of 129131871 is 178131921.

It is a cyclic number.

It is not a de Polignac number, because 129131871 - 2¹ = 129131869 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129131879) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5601 + ... + 17018.

It is an arithmetic number, because the mean of its divisors is an integer number (11807640).

Almost surely, 2^129131871 is an apocalyptic number.

129131871 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

129131871 is a deficient number, since it is larger than the sum of its proper divisors (59790369).

129131871 is a wasteful number, since it uses less digits than its factorization.

129131871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22806.

The product of its digits is 3024, while the sum is 33.

The square root of 129131871 is about 11363.6205058071. The cubic root of 129131871 is about 505.4495503505.

Subtracting 129131871 from its reverse (178131921), we obtain a triangular number (49000050 = T₉₈₉₉).

The spelling of 129131871 in words is "one hundred twenty-nine million, one hundred thirty-one thousand, eight hundred seventy-one".