221221011112121 has 2 divisors, whose sum is σ = 221221011112122. Its totient is φ = 221221011112120.

The previous prime is 221221011112093. The next prime is 221221011112133. The reversal of 221221011112121 is 121211110122122.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 180845610973225 + 40375400138896 = 13447885^2 + 6354164^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221221011112121 is a prime.

It is a super-2 number, since 2×221221011112121² (a number of 29 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 221221011112093 and 221221011112102.

It is not a weakly prime, because it can be changed into another prime (221221011112141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110610505556060 + 110610505556061.

It is an arithmetic number, because the mean of its divisors is an integer number (110610505556061).

Almost surely, 2^{221221011112121} is an apocalyptic number.

It is an amenable number.

221221011112121 is a deficient number, since it is larger than the sum of its proper divisors (1).

221221011112121 is an equidigital number, since it uses as much as digits as its factorization.

221221011112121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 64, while the sum is 20.

Adding to 221221011112121 its reverse (121211110122122), we get a palindrome (342432121234243).

The spelling of 221221011112121 in words is "two hundred twenty-one trillion, two hundred twenty-one billion, eleven million, one hundred twelve thousand, one hundred twenty-one".