129811 has 4 divisors (see below), whose sum is σ = 141624. Its totient is φ = 118000.

The previous prime is 129803. The next prime is 129841. The reversal of 129811 is 118921.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 129811 - 2³ = 129803 is a prime.

It is a Duffinian number.

129811 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (129841) 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 3 ways as a sum of consecutive naturals, for example, 5890 + ... + 5911.

It is an arithmetic number, because the mean of its divisors is an integer number (35406).

2¹²⁹⁸¹¹ is an apocalyptic number.

129811 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

129811 is a deficient number, since it is larger than the sum of its proper divisors (11813).

129811 is a wasteful number, since it uses less digits than its factorization.

129811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11812.

The product of its digits is 144, while the sum is 22.

The square root of 129811 is about 360.2929363726. The cubic root of 129811 is about 50.6334086526.

The spelling of 129811 in words is "one hundred twenty-nine thousand, eight hundred eleven".