221221002221 has 2 divisors, whose sum is σ = 221221002222. Its totient is φ = 221221002220.

The previous prime is 221221002199. The next prime is 221221002287. The reversal of 221221002221 is 122200122122.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 216235230121 + 4985772100 = 465011^2 + 70610^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221221002221 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 221221002221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221221007221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110610501110 + 110610501111.

It is an arithmetic number, because the mean of its divisors is an integer number (110610501111).

Almost surely, 2^221221002221 is an apocalyptic number.

It is an amenable number.

221221002221 is a deficient number, since it is larger than the sum of its proper divisors (1).

221221002221 is an equidigital number, since it uses as much as digits as its factorization.

221221002221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 221221002221 its reverse (122200122122), we get a palindrome (343421124343).

The spelling of 221221002221 in words is "two hundred twenty-one billion, two hundred twenty-one million, two thousand, two hundred twenty-one".