129256109 has 2 divisors, whose sum is σ = 129256110. Its totient is φ = 129256108.

The previous prime is 129256091. The next prime is 129256111. The reversal of 129256109 is 901652921.

Together with previous prime (129256091) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 72675625 + 56580484 = 8525^2 + 7522^2 .

It is a cyclic number.

It is not a de Polignac number, because 129256109 - 2⁸ = 129255853 is a prime.

Together with 129256111, it forms a pair of twin primes.

It is a Chen prime.

It is an alternating number because its digits alternate between odd and even.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (129256009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64628054 + 64628055.

It is an arithmetic number, because the mean of its divisors is an integer number (64628055).

Almost surely, 2^129256109 is an apocalyptic number.

It is an amenable number.

129256109 is a deficient number, since it is larger than the sum of its proper divisors (1).

129256109 is an equidigital number, since it uses as much as digits as its factorization.

129256109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9720, while the sum is 35.

The square root of 129256109 is about 11369.0856712402. The cubic root of 129256109 is about 505.6115963603.

The spelling of 129256109 in words is "one hundred twenty-nine million, two hundred fifty-six thousand, one hundred nine".