213111209 has 2 divisors, whose sum is σ = 213111210. Its totient is φ = 213111208.

The previous prime is 213111203. The next prime is 213111211. The reversal of 213111209 is 902111312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 207216025 + 5895184 = 14395^2 + 2428^2 .

It is a cyclic number.

It is not a de Polignac number, because 213111209 - 2¹⁶ = 213045673 is a prime.

Together with 213111211, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (213111203) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106555604 + 106555605.

It is an arithmetic number, because the mean of its divisors is an integer number (106555605).

Almost surely, 2^213111209 is an apocalyptic number.

It is an amenable number.

213111209 is a deficient number, since it is larger than the sum of its proper divisors (1).

213111209 is an equidigital number, since it uses as much as digits as its factorization.

213111209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 108, while the sum is 20.

The square root of 213111209 is about 14598.3289797155. The cubic root of 213111209 is about 597.3131798067.

The spelling of 213111209 in words is "two hundred thirteen million, one hundred eleven thousand, two hundred nine".