2021021210261 has 2 divisors, whose sum is σ = 2021021210262. Its totient is φ = 2021021210260.

The previous prime is 2021021210249. The next prime is 2021021210267. The reversal of 2021021210261 is 1620121201202.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1707449209636 + 313572000625 = 1306694^2 + 559975^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2021021210261 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2021021210267) 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, 1010510605130 + 1010510605131.

It is an arithmetic number, because the mean of its divisors is an integer number (1010510605131).

Almost surely, 2^{2021021210261} is an apocalyptic number.

It is an amenable number.

2021021210261 is a deficient number, since it is larger than the sum of its proper divisors (1).

2021021210261 is an equidigital number, since it uses as much as digits as its factorization.

2021021210261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 192, while the sum is 20.

Adding to 2021021210261 its reverse (1620121201202), we get a palindrome (3641142411463).

The spelling of 2021021210261 in words is "two trillion, twenty-one billion, twenty-one million, two hundred ten thousand, two hundred sixty-one".