129186809 has 2 divisors, whose sum is σ = 129186810. Its totient is φ = 129186808.

The previous prime is 129186781. The next prime is 129186839. The reversal of 129186809 is 908681921.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 119421184 + 9765625 = 10928^2 + 3125^2 .

It is a cyclic number.

It is not a de Polignac number, because 129186809 - 2²⁰ = 128138233 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 129186809.

It is not a weakly prime, because it can be changed into another prime (129186839) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64593404 + 64593405.

It is an arithmetic number, because the mean of its divisors is an integer number (64593405).

Almost surely, 2^129186809 is an apocalyptic number.

It is an amenable number.

129186809 is a deficient number, since it is larger than the sum of its proper divisors (1).

129186809 is an equidigital number, since it uses as much as digits as its factorization.

129186809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 62208, while the sum is 44.

The square root of 129186809 is about 11366.0375241330. The cubic root of 129186809 is about 505.5212198518.

The spelling of 129186809 in words is "one hundred twenty-nine million, one hundred eighty-six thousand, eight hundred nine".