20021112212221 has 2 divisors, whose sum is σ = 20021112212222. Its totient is φ = 20021112212220.

The previous prime is 20021112212219. The next prime is 20021112212243. The reversal of 20021112212221 is 12221221112002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11659698036900 + 8361414175321 = 3414630^2 + 2891611^2 .

It is a cyclic number.

It is not a de Polignac number, because 20021112212221 - 2¹ = 20021112212219 is a prime.

Together with 20021112212219, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20021112212201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10010556106110 + 10010556106111.

It is an arithmetic number, because the mean of its divisors is an integer number (10010556106111).

Almost surely, 2^{20021112212221} is an apocalyptic number.

It is an amenable number.

20021112212221 is a deficient number, since it is larger than the sum of its proper divisors (1).

20021112212221 is an equidigital number, since it uses as much as digits as its factorization.

20021112212221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 128, while the sum is 19.

Adding to 20021112212221 its reverse (12221221112002), we get a palindrome (32242333324223).

The spelling of 20021112212221 in words is "twenty trillion, twenty-one billion, one hundred twelve million, two hundred twelve thousand, two hundred twenty-one".