21012202202021 has 2 divisors, whose sum is σ = 21012202202022. Its totient is φ = 21012202202020.

The previous prime is 21012202201909. The next prime is 21012202202023. The reversal of 21012202202021 is 12020220221012.

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., 20973780321796 + 38421880225 = 4579714^2 + 196015^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21012202202021 is a prime.

It is a super-2 number, since 2×21012202202021² (a number of 27 digits) contains 22 as substring.

Together with 21012202202023, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21012202202023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506101101010 + 10506101101011.

It is an arithmetic number, because the mean of its divisors is an integer number (10506101101011).

Almost surely, 2^{21012202202021} is an apocalyptic number.

It is an amenable number.

21012202202021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21012202202021 is an equidigital number, since it uses as much as digits as its factorization.

21012202202021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 21012202202021 its reverse (12020220221012), we get a palindrome (33032422423033).

The spelling of 21012202202021 in words is "twenty-one trillion, twelve billion, two hundred two million, two hundred two thousand, twenty-one".