211204122221 has 2 divisors, whose sum is σ = 211204122222. Its totient is φ = 211204122220.

The previous prime is 211204122191. The next prime is 211204122251. The reversal of 211204122221 is 122221402112.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (211204122191) and next prime (211204122251).

It can be written as a sum of positive squares in only one way, i.e., 209438946025 + 1765176196 = 457645^2 + 42014^2 .

It is a cyclic number.

It is not a de Polignac number, because 211204122221 - 2¹⁰ = 211204121197 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 211204122193 and 211204122202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (211204122251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105602061110 + 105602061111.

It is an arithmetic number, because the mean of its divisors is an integer number (105602061111).

Almost surely, 2^211204122221 is an apocalyptic number.

It is an amenable number.

211204122221 is a deficient number, since it is larger than the sum of its proper divisors (1).

211204122221 is an equidigital number, since it uses as much as digits as its factorization.

211204122221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 256, while the sum is 20.

Adding to 211204122221 its reverse (122221402112), we get a palindrome (333425524333).

The spelling of 211204122221 in words is "two hundred eleven billion, two hundred four million, one hundred twenty-two thousand, two hundred twenty-one".