20110121210021 has 2 divisors, whose sum is σ = 20110121210022. Its totient is φ = 20110121210020.

The previous prime is 20110121209951. The next prime is 20110121210063. The reversal of 20110121210021 is 12001212101102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19345799404996 + 764321805025 = 4398386^2 + 874255^2 .

It is a cyclic number.

It is not a de Polignac number, because 20110121210021 - 2²⁶ = 20110054101157 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20110121209978 and 20110121210005.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20110121216021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10055060605010 + 10055060605011.

It is an arithmetic number, because the mean of its divisors is an integer number (10055060605011).

Almost surely, 2^{20110121210021} is an apocalyptic number.

It is an amenable number.

20110121210021 is a deficient number, since it is larger than the sum of its proper divisors (1).

20110121210021 is an equidigital number, since it uses as much as digits as its factorization.

20110121210021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 20110121210021 its reverse (12001212101102), we get a palindrome (32111333311123).

The spelling of 20110121210021 in words is "twenty trillion, one hundred ten billion, one hundred twenty-one million, two hundred ten thousand, twenty-one".