211820129 has 4 divisors (see below), whose sum is σ = 213917460. Its totient is φ = 209722800.

The previous prime is 211820111. The next prime is 211820143. The reversal of 211820129 is 921028112.

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

It can be written as a sum of positive squares in 2 ways, for example, as 161976529 + 49843600 = 12727^2 + 7060^2 .

It is a cyclic number.

It is not a de Polignac number, because 211820129 - 2²⁰ = 210771553 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 211820098 and 211820107.

It is not an unprimeable number, because it can be changed into a prime (211820149) 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, 1048514 + ... + 1048715.

It is an arithmetic number, because the mean of its divisors is an integer number (53479365).

Almost surely, 2^211820129 is an apocalyptic number.

It is an amenable number.

211820129 is a deficient number, since it is larger than the sum of its proper divisors (2097331).

211820129 is a wasteful number, since it uses less digits than its factorization.

211820129 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2097330.

The product of its (nonzero) digits is 576, while the sum is 26.

The square root of 211820129 is about 14554.0416723328. The cubic root of 211820129 is about 596.1045124364.

The spelling of 211820129 in words is "two hundred eleven million, eight hundred twenty thousand, one hundred twenty-nine".