21120120212221 has 2 divisors, whose sum is σ = 21120120212222. Its totient is φ = 21120120212220.

The previous prime is 21120120212207. The next prime is 21120120212231. The reversal of 21120120212221 is 12221202102112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20484576428121 + 635543784100 = 4525989^2 + 797210^2 .

It is a cyclic number.

It is not a de Polignac number, because 21120120212221 - 2⁹ = 21120120211709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21120120212231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560060106110 + 10560060106111.

It is an arithmetic number, because the mean of its divisors is an integer number (10560060106111).

Almost surely, 2^{21120120212221} is an apocalyptic number.

It is an amenable number.

21120120212221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21120120212221 is an equidigital number, since it uses as much as digits as its factorization.

21120120212221 is an evil number, because the sum of its binary digits is even.

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

Adding to 21120120212221 its reverse (12221202102112), we get a palindrome (33341322314333).

The spelling of 21120120212221 in words is "twenty-one trillion, one hundred twenty billion, one hundred twenty million, two hundred twelve thousand, two hundred twenty-one".