21020122021081 has 2 divisors, whose sum is σ = 21020122021082. Its totient is φ = 21020122021080.

The previous prime is 21020122021061. The next prime is 21020122021231. The reversal of 21020122021081 is 18012022102012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20324399211081 + 695722810000 = 4508259^2 + 834100^2 .

It is a cyclic number.

It is not a de Polignac number, because 21020122021081 - 2¹¹ = 21020122019033 is a prime.

It is a super-2 number, since 2×21020122021081² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21020122021061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510061010540 + 10510061010541.

It is an arithmetic number, because the mean of its divisors is an integer number (10510061010541).

Almost surely, 2^{21020122021081} is an apocalyptic number.

It is an amenable number.

21020122021081 is a deficient number, since it is larger than the sum of its proper divisors (1).

21020122021081 is an equidigital number, since it uses as much as digits as its factorization.

21020122021081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 256, while the sum is 22.

Adding to 21020122021081 its reverse (18012022102012), we get a palindrome (39032144123093).

The spelling of 21020122021081 in words is "twenty-one trillion, twenty billion, one hundred twenty-two million, twenty-one thousand, eighty-one".