211871813 has 2 divisors, whose sum is σ = 211871814. Its totient is φ = 211871812.

The previous prime is 211871797. The next prime is 211871819. The reversal of 211871813 is 318178112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 200024449 + 11847364 = 14143^2 + 3442^2 .

It is a cyclic number.

It is not a de Polignac number, because 211871813 - 2⁴ = 211871797 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 211871813.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (211871819) 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, 105935906 + 105935907.

It is an arithmetic number, because the mean of its divisors is an integer number (105935907).

Almost surely, 2^211871813 is an apocalyptic number.

It is an amenable number.

211871813 is a deficient number, since it is larger than the sum of its proper divisors (1).

211871813 is an equidigital number, since it uses as much as digits as its factorization.

211871813 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2688, while the sum is 32.

The square root of 211871813 is about 14555.8171532896. The cubic root of 211871813 is about 596.1529915561.

The spelling of 211871813 in words is "two hundred eleven million, eight hundred seventy-one thousand, eight hundred thirteen".