129805 has 8 divisors (see below), whose sum is σ = 167832. Its totient is φ = 95808.

The previous prime is 129803. The next prime is 129841. The reversal of 129805 is 508921.

It can be written as a sum of positive squares in 4 ways, for example, as 4489 + 125316 = 67^2 + 354^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 129805 - 2¹ = 129803 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 129805.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 934 + ... + 1063.

It is an arithmetic number, because the mean of its divisors is an integer number (20979).

2¹²⁹⁸⁰⁵ is an apocalyptic number.

It is an amenable number.

129805 is a deficient number, since it is larger than the sum of its proper divisors (38027).

129805 is a wasteful number, since it uses less digits than its factorization.

129805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2015.

The product of its (nonzero) digits is 720, while the sum is 25.

The square root of 129805 is about 360.2846097185. The cubic root of 129805 is about 50.6326285309.

The spelling of 129805 in words is "one hundred twenty-nine thousand, eight hundred five".