129509 has 2 divisors, whose sum is σ = 129510. Its totient is φ = 129508.

The previous prime is 129499. The next prime is 129517. The reversal of 129509 is 905921.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 124609 + 4900 = 353^2 + 70^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-129509 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (129529) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64754 + 64755.

It is an arithmetic number, because the mean of its divisors is an integer number (64755).

2¹²⁹⁵⁰⁹ is an apocalyptic number.

It is an amenable number.

129509 is a deficient number, since it is larger than the sum of its proper divisors (1).

129509 is an equidigital number, since it uses as much as digits as its factorization.

129509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 810, while the sum is 26.

The square root of 129509 is about 359.8735889170. The cubic root of 129509 is about 50.5941126428.

The spelling of 129509 in words is "one hundred twenty-nine thousand, five hundred nine".