129520509 has 4 divisors (see below), whose sum is σ = 172694016. Its totient is φ = 86347004.

The previous prime is 129520483. The next prime is 129520529. The reversal of 129520509 is 905025921.

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 cyclic number.

It is not a de Polignac number, because 129520509 - 2⁸ = 129520253 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 129520509.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129520529) 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, 21586749 + ... + 21586754.

It is an arithmetic number, because the mean of its divisors is an integer number (43173504).

Almost surely, 2^129520509 is an apocalyptic number.

It is an amenable number.

129520509 is a deficient number, since it is larger than the sum of its proper divisors (43173507).

129520509 is an equidigital number, since it uses as much as digits as its factorization.

129520509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43173506.

The product of its (nonzero) digits is 8100, while the sum is 33.

The square root of 129520509 is about 11380.7077547928. The cubic root of 129520509 is about 505.9561130418.

The spelling of 129520509 in words is "one hundred twenty-nine million, five hundred twenty thousand, five hundred nine".