129576128521 has 4 divisors (see below), whose sum is σ = 148087004032. Its totient is φ = 111065253012.

The previous prime is 129576128497. The next prime is 129576128543. The reversal of 129576128521 is 125821675921.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a de Polignac number, because none of the positive numbers 2^k-129576128521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (129576128581) 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 3 ways as a sum of consecutive naturals, for example, 9255437745 + ... + 9255437758.

It is an arithmetic number, because the mean of its divisors is an integer number (37021751008).

Almost surely, 2^129576128521 is an apocalyptic number.

It is an amenable number.

129576128521 is a deficient number, since it is larger than the sum of its proper divisors (18510875511).

129576128521 is an equidigital number, since it uses as much as digits as its factorization.

129576128521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18510875510.

The product of its digits is 604800, while the sum is 49.

The spelling of 129576128521 in words is "one hundred twenty-nine billion, five hundred seventy-six million, one hundred twenty-eight thousand, five hundred twenty-one".