21022204121 has 2 divisors, whose sum is σ = 21022204122. Its totient is φ = 21022204120.

The previous prime is 21022204111. The next prime is 21022204129. The reversal of 21022204121 is 12140222012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20910606025 + 111598096 = 144605^2 + 10564^2 .

It is a cyclic number.

It is not a de Polignac number, because 21022204121 - 2¹⁴ = 21022187737 is a prime.

It is a super-2 number, since 2×21022204121² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21022204121.

It is not a weakly prime, because it can be changed into another prime (21022204129) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10511102060 + 10511102061.

It is an arithmetic number, because the mean of its divisors is an integer number (10511102061).

Almost surely, 2^21022204121 is an apocalyptic number.

It is an amenable number.

21022204121 is a deficient number, since it is larger than the sum of its proper divisors (1).

21022204121 is an equidigital number, since it uses as much as digits as its factorization.

21022204121 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 17.

Adding to 21022204121 its reverse (12140222012), we get a palindrome (33162426133).

The spelling of 21022204121 in words is "twenty-one billion, twenty-two million, two hundred four thousand, one hundred twenty-one".