21202122202981 has 2 divisors, whose sum is σ = 21202122202982. Its totient is φ = 21202122202980.

The previous prime is 21202122202879. The next prime is 21202122202991. The reversal of 21202122202981 is 18920222120212.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17695828502881 + 3506293700100 = 4206641^2 + 1872510^2 .

It is a cyclic number.

It is not a de Polignac number, because 21202122202981 - 2¹⁷ = 21202122071909 is a prime.

It is a super-3 number, since 3×21202122202981³ (a number of 41 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21202122202991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10601061101490 + 10601061101491.

It is an arithmetic number, because the mean of its divisors is an integer number (10601061101491).

Almost surely, 2^{21202122202981} is an apocalyptic number.

It is an amenable number.

21202122202981 is a deficient number, since it is larger than the sum of its proper divisors (1).

21202122202981 is an equidigital number, since it uses as much as digits as its factorization.

21202122202981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9216, while the sum is 34.

The spelling of 21202122202981 in words is "twenty-one trillion, two hundred two billion, one hundred twenty-two million, two hundred two thousand, nine hundred eighty-one".