129256220417 has 2 divisors, whose sum is σ = 129256220418. Its totient is φ = 129256220416.

The previous prime is 129256220399. The next prime is 129256220441. The reversal of 129256220417 is 714022652921.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 121775873296 + 7480347121 = 348964^2 + 86489^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-129256220417 is a prime.

It is not a weakly prime, because it can be changed into another prime (129256220447) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64628110208 + 64628110209.

It is an arithmetic number, because the mean of its divisors is an integer number (64628110209).

Almost surely, 2^129256220417 is an apocalyptic number.

It is an amenable number.

129256220417 is a deficient number, since it is larger than the sum of its proper divisors (1).

129256220417 is an equidigital number, since it uses as much as digits as its factorization.

129256220417 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 120960, while the sum is 41.

The spelling of 129256220417 in words is "one hundred twenty-nine billion, two hundred fifty-six million, two hundred twenty thousand, four hundred seventeen".