21202001110021 has 2 divisors, whose sum is σ = 21202001110022. Its totient is φ = 21202001110020.

The previous prime is 21202001110019. The next prime is 21202001110039. The reversal of 21202001110021 is 12001110020212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12420937192225 + 8781063917796 = 3524335^2 + 2963286^2 .

It is a cyclic number.

It is not a de Polignac number, because 21202001110021 - 2¹ = 21202001110019 is a prime.

It is a super-2 number, since 2×21202001110021² (a number of 27 digits) contains 22 as substring.

Together with 21202001110019, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 21202001109983 and 21202001110010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21202001110001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10601000555010 + 10601000555011.

It is an arithmetic number, because the mean of its divisors is an integer number (10601000555011).

Almost surely, 2^{21202001110021} is an apocalyptic number.

It is an amenable number.

21202001110021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21202001110021 is an equidigital number, since it uses as much as digits as its factorization.

21202001110021 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 13.

Adding to 21202001110021 its reverse (12001110020212), we get a palindrome (33203111130233).

The spelling of 21202001110021 in words is "twenty-one trillion, two hundred two billion, one million, one hundred ten thousand, twenty-one".