210221210021 has 2 divisors, whose sum is σ = 210221210022. Its totient is φ = 210221210020.

The previous prime is 210221209999. The next prime is 210221210033. The reversal of 210221210021 is 120012122012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 187536633025 + 22684576996 = 433055^2 + 150614^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-210221210021 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 210221209978 and 210221210005.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (210221210051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105110605010 + 105110605011.

It is an arithmetic number, because the mean of its divisors is an integer number (105110605011).

Almost surely, 2^210221210021 is an apocalyptic number.

It is an amenable number.

210221210021 is a deficient number, since it is larger than the sum of its proper divisors (1).

210221210021 is an equidigital number, since it uses as much as digits as its factorization.

210221210021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 210221210021 its reverse (120012122012), we get a palindrome (330233332033).

The spelling of 210221210021 in words is "two hundred ten billion, two hundred twenty-one million, two hundred ten thousand, twenty-one".