129200009 has 2 divisors, whose sum is σ = 129200010. Its totient is φ = 129200008.

The previous prime is 129199969. The next prime is 129200011. The reversal of 129200009 is 900002921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 110838784 + 18361225 = 10528^2 + 4285^2 .

It is a cyclic number.

It is not a de Polignac number, because 129200009 - 2²⁰ = 128151433 is a prime.

Together with 129200011, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (129200059) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64600004 + 64600005.

It is an arithmetic number, because the mean of its divisors is an integer number (64600005).

Almost surely, 2^129200009 is an apocalyptic number.

It is an amenable number.

129200009 is a deficient number, since it is larger than the sum of its proper divisors (1).

129200009 is an equidigital number, since it uses as much as digits as its factorization.

129200009 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 129200009 is about 11366.6181866024. The cubic root of 129200009 is about 505.5384369163.

The spelling of 129200009 in words is "one hundred twenty-nine million, two hundred thousand, nine".