221312112221 has 2 divisors, whose sum is σ = 221312112222. Its totient is φ = 221312112220.

The previous prime is 221312112211. The next prime is 221312112251. The reversal of 221312112221 is 122211213122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 148201900900 + 73110211321 = 384970^2 + 270389^2 .

It is a cyclic number.

It is not a de Polignac number, because 221312112221 - 2¹⁰ = 221312111197 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 221312112193 and 221312112202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221312112211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110656056110 + 110656056111.

It is an arithmetic number, because the mean of its divisors is an integer number (110656056111).

Almost surely, 2^221312112221 is an apocalyptic number.

It is an amenable number.

221312112221 is a deficient number, since it is larger than the sum of its proper divisors (1).

221312112221 is an equidigital number, since it uses as much as digits as its factorization.

221312112221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 192, while the sum is 20.

Adding to 221312112221 its reverse (122211213122), we get a palindrome (343523325343).

The spelling of 221312112221 in words is "two hundred twenty-one billion, three hundred twelve million, one hundred twelve thousand, two hundred twenty-one".