129309 has 4 divisors (see below), whose sum is σ = 172416. Its totient is φ = 86204.

The previous prime is 129293. The next prime is 129313. The reversal of 129309 is 903921.

It is a happy number.

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 129309 - 2⁴ = 129293 is a prime.

It is a D-number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129379) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21549 + ... + 21554.

It is an arithmetic number, because the mean of its divisors is an integer number (43104).

2¹²⁹³⁰⁹ is an apocalyptic number.

It is an amenable number.

129309 is a deficient number, since it is larger than the sum of its proper divisors (43107).

129309 is an equidigital number, since it uses as much as digits as its factorization.

129309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43106.

The product of its (nonzero) digits is 486, while the sum is 24.

The square root of 129309 is about 359.5956062023. The cubic root of 129309 is about 50.5680551595.

Adding to 129309 its product of nonzero digits (486), we get a triangular number (129795 = T₅₀₉).

The spelling of 129309 in words is "one hundred twenty-nine thousand, three hundred nine".