1212121200221 has 2 divisors, whose sum is σ = 1212121200222. Its totient is φ = 1212121200220.

The previous prime is 1212121200209. The next prime is 1212121200223. The reversal of 1212121200221 is 1220021212121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 996582924100 + 215538276121 = 998290^2 + 464261^2 .

It is a cyclic number.

It is not a de Polignac number, because 1212121200221 - 2¹⁴ = 1212121183837 is a prime.

Together with 1212121200223, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1212121200221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1212121200223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 606060600110 + 606060600111.

It is an arithmetic number, because the mean of its divisors is an integer number (606060600111).

Almost surely, 2^{1212121200221} is an apocalyptic number.

It is an amenable number.

1212121200221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1212121200221 is an equidigital number, since it uses as much as digits as its factorization.

1212121200221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 1212121200221 its reverse (1220021212121), we get a palindrome (2432142412342).

The spelling of 1212121200221 in words is "one trillion, two hundred twelve billion, one hundred twenty-one million, two hundred thousand, two hundred twenty-one".