129434561 has 2 divisors, whose sum is σ = 129434562. Its totient is φ = 129434560.

The previous prime is 129434537. The next prime is 129434563. The reversal of 129434561 is 165434921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 128686336 + 748225 = 11344^2 + 865^2 .

It is a cyclic number.

It is not a de Polignac number, because 129434561 - 2²² = 125240257 is a prime.

It is a Sophie Germain prime.

Together with 129434563, 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 Curzon number.

It is not a weakly prime, because it can be changed into another prime (129434563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64717280 + 64717281.

It is an arithmetic number, because the mean of its divisors is an integer number (64717281).

Almost surely, 2^129434561 is an apocalyptic number.

It is an amenable number.

129434561 is a deficient number, since it is larger than the sum of its proper divisors (1).

129434561 is an equidigital number, since it uses as much as digits as its factorization.

129434561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 25920, while the sum is 35.

The square root of 129434561 is about 11376.9310888306. The cubic root of 129434561 is about 505.8441731419.

The spelling of 129434561 in words is "one hundred twenty-nine million, four hundred thirty-four thousand, five hundred sixty-one".