211686012221 has 2 divisors, whose sum is σ = 211686012222. Its totient is φ = 211686012220.

The previous prime is 211686012217. The next prime is 211686012269. The reversal of 211686012221 is 122210686112.

211686012221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 158412756121 + 53273256100 = 398011^2 + 230810^2 .

It is a cyclic number.

It is not a de Polignac number, because 211686012221 - 2² = 211686012217 is a prime.

It is a super-2 number, since 2×211686012221² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (211686011221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105843006110 + 105843006111.

It is an arithmetic number, because the mean of its divisors is an integer number (105843006111).

Almost surely, 2^211686012221 is an apocalyptic number.

It is an amenable number.

211686012221 is a deficient number, since it is larger than the sum of its proper divisors (1).

211686012221 is an equidigital number, since it uses as much as digits as its factorization.

211686012221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4608, while the sum is 32.

Adding to 211686012221 its reverse (122210686112), we get a palindrome (333896698333).

The spelling of 211686012221 in words is "two hundred eleven billion, six hundred eighty-six million, twelve thousand, two hundred twenty-one".