1212101222221 has 2 divisors, whose sum is σ = 1212101222222. Its totient is φ = 1212101222220.

The previous prime is 1212101222219. The next prime is 1212101222239. The reversal of 1212101222221 is 1222221012121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1180634364900 + 31466857321 = 1086570^2 + 177389^2 .

It is an emirp because it is prime and its reverse (1222221012121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1212101222221 - 2¹ = 1212101222219 is a prime.

Together with 1212101222219, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1212101222291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 606050611110 + 606050611111.

It is an arithmetic number, because the mean of its divisors is an integer number (606050611111).

Almost surely, 2^{1212101222221} is an apocalyptic number.

It is an amenable number.

1212101222221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1212101222221 is an equidigital number, since it uses as much as digits as its factorization.

1212101222221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 128, while the sum is 19.

Adding to 1212101222221 its reverse (1222221012121), we get a palindrome (2434322234342).

It can be divided in two parts, 121210 and 1222221, that added together give a palindrome (1343431).

The spelling of 1212101222221 in words is "one trillion, two hundred twelve billion, one hundred one million, two hundred twenty-two thousand, two hundred twenty-one".