129000205 has 4 divisors (see below), whose sum is σ = 154800252. Its totient is φ = 103200160.

The previous prime is 129000197. The next prime is 129000211. The reversal of 129000205 is 502000921.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 502000921 = 23 ⋅21826127.

It can be written as a sum of positive squares in 2 ways, for example, as 53275401 + 75724804 = 7299^2 + 8702^2 .

It is not a de Polignac number, because 129000205 - 2³ = 129000197 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12900016 + ... + 12900025.

It is an arithmetic number, because the mean of its divisors is an integer number (38700063).

Almost surely, 2^129000205 is an apocalyptic number.

It is an amenable number.

129000205 is a deficient number, since it is larger than the sum of its proper divisors (25800047).

129000205 is an equidigital number, since it uses as much as digits as its factorization.

129000205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25800046.

The product of its (nonzero) digits is 180, while the sum is 19.

The square root of 129000205 is about 11357.8257162188. The cubic root of 129000205 is about 505.2777023741.

The spelling of 129000205 in words is "one hundred twenty-nine million, two hundred five", and thus it is an aban number.