21220220200121 has 2 divisors, whose sum is σ = 21220220200122. Its totient is φ = 21220220200120.

The previous prime is 21220220200097. The next prime is 21220220200169. The reversal of 21220220200121 is 12100202202212.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19094059605625 + 2126160594496 = 4369675^2 + 1458136^2 .

It is a cyclic number.

It is not a de Polignac number, because 21220220200121 - 2¹⁰ = 21220220199097 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21220220200121.

It is not a weakly prime, because it can be changed into another prime (21220220200021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610110100060 + 10610110100061.

It is an arithmetic number, because the mean of its divisors is an integer number (10610110100061).

Almost surely, 2^{21220220200121} is an apocalyptic number.

It is an amenable number.

21220220200121 is a deficient number, since it is larger than the sum of its proper divisors (1).

21220220200121 is an equidigital number, since it uses as much as digits as its factorization.

21220220200121 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 21220220200121 its reverse (12100202202212), we get a palindrome (33320422402333).

The spelling of 21220220200121 in words is "twenty-one trillion, two hundred twenty billion, two hundred twenty million, two hundred thousand, one hundred twenty-one".