129122809 has 2 divisors, whose sum is σ = 129122810. Its totient is φ = 129122808.

The previous prime is 129122797. The next prime is 129122827. The reversal of 129122809 is 908221921.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 127690000 + 1432809 = 11300^2 + 1197^2 .

It is a cyclic number.

It is not a de Polignac number, because 129122809 - 2¹⁵ = 129090041 is a prime.

It is not a weakly prime, because it can be changed into another prime (129122839) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64561404 + 64561405.

It is an arithmetic number, because the mean of its divisors is an integer number (64561405).

Almost surely, 2^129122809 is an apocalyptic number.

It is an amenable number.

129122809 is a deficient number, since it is larger than the sum of its proper divisors (1).

129122809 is an equidigital number, since it uses as much as digits as its factorization.

129122809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5184, while the sum is 34.

The square root of 129122809 is about 11363.2217702551. The cubic root of 129122809 is about 505.4377265435.

The spelling of 129122809 in words is "one hundred twenty-nine million, one hundred twenty-two thousand, eight hundred nine".