221221001220221 has 2 divisors, whose sum is σ = 221221001220222. Its totient is φ = 221221001220220.

The previous prime is 221221001220143. The next prime is 221221001220227. The reversal of 221221001220221 is 122022100122122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 123821590075225 + 97399411144996 = 11127515^2 + 9869114^2 .

It is a cyclic number.

It is not a de Polignac number, because 221221001220221 - 2¹⁴ = 221221001203837 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 221221001220193 and 221221001220202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221221001220227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110610500610110 + 110610500610111.

It is an arithmetic number, because the mean of its divisors is an integer number (110610500610111).

Almost surely, 2^{221221001220221} is an apocalyptic number.

It is an amenable number.

221221001220221 is a deficient number, since it is larger than the sum of its proper divisors (1).

221221001220221 is an equidigital number, since it uses as much as digits as its factorization.

221221001220221 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 221221001220221 its reverse (122022100122122), we get a palindrome (343243101342343).

The spelling of 221221001220221 in words is "two hundred twenty-one trillion, two hundred twenty-one billion, one million, two hundred twenty thousand, two hundred twenty-one".