129209 has 2 divisors, whose sum is σ = 129210. Its totient is φ = 129208.

The previous prime is 129197. The next prime is 129221. The reversal of 129209 is 902921.

It is a balanced prime because it is at equal distance from previous prime (129197) and next prime (129221).

It can be written as a sum of positive squares in only one way, i.e., 73984 + 55225 = 272^2 + 235^2 .

It is a cyclic number.

It is not a de Polignac number, because 129209 - 2⁴ = 129193 is a prime.

It is a Chen prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 129209.

It is not a weakly prime, because it can be changed into another prime (129229) 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 as a sum of consecutive naturals, namely, 64604 + 64605.

It is an arithmetic number, because the mean of its divisors is an integer number (64605).

2¹²⁹²⁰⁹ is an apocalyptic number.

It is an amenable number.

129209 is a deficient number, since it is larger than the sum of its proper divisors (1).

129209 is an equidigital number, since it uses as much as digits as its factorization.

129209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 324, while the sum is 23.

The square root of 129209 is about 359.4565342291. The cubic root of 129209 is about 50.5550163414. Note that the first 3 decimals are identical.

The spelling of 129209 in words is "one hundred twenty-nine thousand, two hundred nine".