20100121202221 has 2 divisors, whose sum is σ = 20100121202222. Its totient is φ = 20100121202220.

The previous prime is 20100121202201. The next prime is 20100121202237. The reversal of 20100121202221 is 12220212100102.

It is a happy number.

It is an a-pointer prime, because the next prime (20100121202237) can be obtained adding 20100121202221 to its sum of digits (16).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16280305032996 + 3819816169225 = 4034886^2 + 1954435^2 .

It is a cyclic number.

It is not a de Polignac number, because 20100121202221 - 2²⁵ = 20100087647789 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20100121202195 and 20100121202204.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20100121202201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10050060601110 + 10050060601111.

It is an arithmetic number, because the mean of its divisors is an integer number (10050060601111).

Almost surely, 2^{20100121202221} is an apocalyptic number.

It is an amenable number.

20100121202221 is a deficient number, since it is larger than the sum of its proper divisors (1).

20100121202221 is an equidigital number, since it uses as much as digits as its factorization.

20100121202221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 20100121202221 its reverse (12220212100102), we get a palindrome (32320333302323).

The spelling of 20100121202221 in words is "twenty trillion, one hundred billion, one hundred twenty-one million, two hundred two thousand, two hundred twenty-one".