2121012020221 has 2 divisors, whose sum is σ = 2121012020222. Its totient is φ = 2121012020220.

The previous prime is 2121012020219. The next prime is 2121012020279. The reversal of 2121012020221 is 1220202101212.

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., 1557476544121 + 563535476100 = 1247989^2 + 750690^2 .

It is a cyclic number.

It is not a de Polignac number, because 2121012020221 - 2¹ = 2121012020219 is a prime.

Together with 2121012020219, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 2121012020195 and 2121012020204.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2121012320221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1060506010110 + 1060506010111.

It is an arithmetic number, because the mean of its divisors is an integer number (1060506010111).

Almost surely, 2^{2121012020221} is an apocalyptic number.

It is an amenable number.

2121012020221 is a deficient number, since it is larger than the sum of its proper divisors (1).

2121012020221 is an equidigital number, since it uses as much as digits as its factorization.

2121012020221 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 16.

Adding to 2121012020221 its reverse (1220202101212), we get a palindrome (3341214121433).

It can be divided in two parts, 212101 and 2020221, that added together give a palindrome (2232322).

The spelling of 2121012020221 in words is "two trillion, one hundred twenty-one billion, twelve million, twenty thousand, two hundred twenty-one".