2021210212121 has 2 divisors, whose sum is σ = 2021210212122. Its totient is φ = 2021210212120.

The previous prime is 2021210212039. The next prime is 2021210212129. The reversal of 2021210212121 is 1212120121202.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1411153926400 + 610056285721 = 1187920^2 + 781061^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2021210212121 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 2021210212121.

It is not a weakly prime, because it can be changed into another prime (2021210212129) 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, 1010605106060 + 1010605106061.

It is an arithmetic number, because the mean of its divisors is an integer number (1010605106061).

Almost surely, 2^{2021210212121} is an apocalyptic number.

It is an amenable number.

2021210212121 is a deficient number, since it is larger than the sum of its proper divisors (1).

2021210212121 is an equidigital number, since it uses as much as digits as its factorization.

2021210212121 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 2021210212121 its reverse (1212120121202), we get a palindrome (3233330333323).

The spelling of 2021210212121 in words is "two trillion, twenty-one billion, two hundred ten million, two hundred twelve thousand, one hundred twenty-one".