221211011221 has 2 divisors, whose sum is σ = 221211011222. Its totient is φ = 221211011220.

The previous prime is 221211011213. The next prime is 221211011237. The reversal of 221211011221 is 122110112122.

It is an a-pointer prime, because the next prime (221211011237) can be obtained adding 221211011221 to its sum of digits (16).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 198443520900 + 22767490321 = 445470^2 + 150889^2 .

It is a cyclic number.

It is not a de Polignac number, because 221211011221 - 2³ = 221211011213 is a prime.

It is a super-2 number, since 2×221211011221² (a number of 23 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 221211011195 and 221211011204.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221211011261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110605505610 + 110605505611.

It is an arithmetic number, because the mean of its divisors is an integer number (110605505611).

Almost surely, 2^221211011221 is an apocalyptic number.

It is an amenable number.

221211011221 is a deficient number, since it is larger than the sum of its proper divisors (1).

221211011221 is an equidigital number, since it uses as much as digits as its factorization.

221211011221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 221211011221 its reverse (122110112122), we get a palindrome (343321123343).

The spelling of 221211011221 in words is "two hundred twenty-one billion, two hundred eleven million, eleven thousand, two hundred twenty-one".