21021021222121 has 2 divisors, whose sum is σ = 21021021222122. Its totient is φ = 21021021222120.

The previous prime is 21021021222083. The next prime is 21021021222139. The reversal of 21021021222121 is 12122212012012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17656291359721 + 3364729862400 = 4201939^2 + 1834320^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21021021222121 is a prime.

It is a super-2 number, since 2×21021021222121² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21021021222191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510510611060 + 10510510611061.

It is an arithmetic number, because the mean of its divisors is an integer number (10510510611061).

Almost surely, 2^{21021021222121} is an apocalyptic number.

It is an amenable number.

21021021222121 is a deficient number, since it is larger than the sum of its proper divisors (1).

21021021222121 is an equidigital number, since it uses as much as digits as its factorization.

21021021222121 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 21021021222121 its reverse (12122212012012), we get a palindrome (33143233234133).

The spelling of 21021021222121 in words is "twenty-one trillion, twenty-one billion, twenty-one million, two hundred twenty-two thousand, one hundred twenty-one".