1020212121221 has 2 divisors, whose sum is σ = 1020212121222. Its totient is φ = 1020212121220.

The previous prime is 1020212121167. The next prime is 1020212121239. The reversal of 1020212121221 is 1221212120201.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 894463869121 + 125748252100 = 945761^2 + 354610^2 .

It is a cyclic number.

It is not a de Polignac number, because 1020212121221 - 2¹⁰ = 1020212120197 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1020212121221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1020212121421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 510106060610 + 510106060611.

It is an arithmetic number, because the mean of its divisors is an integer number (510106060611).

Almost surely, 2^{1020212121221} is an apocalyptic number.

It is an amenable number.

1020212121221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1020212121221 is an equidigital number, since it uses as much as digits as its factorization.

1020212121221 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 17.

Adding to 1020212121221 its reverse (1221212120201), we get a palindrome (2241424241422).

The spelling of 1020212121221 in words is "one trillion, twenty billion, two hundred twelve million, one hundred twenty-one thousand, two hundred twenty-one".