211811 has 2 divisors, whose sum is σ = 211812. Its totient is φ = 211810.

The previous prime is 211801. The next prime is 211817. The reversal of 211811 is 118112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 211811 - 2⁶ = 211747 is a prime.

It is a Chen prime.

It is a nialpdrome in base 13.

It is not a weakly prime, because it can be changed into another prime (211817) 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 as a sum of consecutive naturals, namely, 105905 + 105906.

It is an arithmetic number, because the mean of its divisors is an integer number (105906).

2²¹¹⁸¹¹ is an apocalyptic number.

211811 is a deficient number, since it is larger than the sum of its proper divisors (1).

211811 is an equidigital number, since it uses as much as digits as its factorization.

211811 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16, while the sum is 14.

The square root of 211811 is about 460.2292906802. The cubic root of 211811 is about 59.6095948698.

Adding to 211811 its reverse (118112), we get a palindrome (329923).

The spelling of 211811 in words is "two hundred eleven thousand, eight hundred eleven".