21010122202109 has 2 divisors, whose sum is σ = 21010122202110. Its totient is φ = 21010122202108.

The previous prime is 21010122202039. The next prime is 21010122202229. The reversal of 21010122202109 is 90120222101012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10574495904025 + 10435626298084 = 3251845^2 + 3230422^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21010122202109 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21010122202009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505061101054 + 10505061101055.

It is an arithmetic number, because the mean of its divisors is an integer number (10505061101055).

Almost surely, 2^{21010122202109} is an apocalyptic number.

It is an amenable number.

21010122202109 is a deficient number, since it is larger than the sum of its proper divisors (1).

21010122202109 is an equidigital number, since it uses as much as digits as its factorization.

21010122202109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 23.

The spelling of 21010122202109 in words is "twenty-one trillion, ten billion, one hundred twenty-two million, two hundred two thousand, one hundred nine".