211830121 has 4 divisors (see below), whose sum is σ = 211994244. Its totient is φ = 211666000.

The previous prime is 211830097. The next prime is 211830137. The reversal of 211830121 is 121038112.

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 31304025 + 180526096 = 5595^2 + 13436^2 .

It is a cyclic number.

It is not a de Polignac number, because 211830121 - 2¹¹ = 211828073 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (211830721) 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, 80110 + ... + 82711.

It is an arithmetic number, because the mean of its divisors is an integer number (52998561).

Almost surely, 2^211830121 is an apocalyptic number.

It is an amenable number.

211830121 is a deficient number, since it is larger than the sum of its proper divisors (164123).

211830121 is a wasteful number, since it uses less digits than its factorization.

211830121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 164122.

The product of its (nonzero) digits is 96, while the sum is 19.

The square root of 211830121 is about 14554.3849406287. The cubic root of 211830121 is about 596.1138854559.

Adding to 211830121 its reverse (121038112), we get a palindrome (332868233).

The spelling of 211830121 in words is "two hundred eleven million, eight hundred thirty thousand, one hundred twenty-one".