21012202021021 has 2 divisors, whose sum is σ = 21012202021022. Its totient is φ = 21012202021020.

The previous prime is 21012202020881. The next prime is 21012202021033. The reversal of 21012202021021 is 12012020221012.

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., 20096266888996 + 915935132025 = 4482886^2 + 957045^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21012202021021 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21012202020986 and 21012202021004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21012202121021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506101010510 + 10506101010511.

It is an arithmetic number, because the mean of its divisors is an integer number (10506101010511).

Almost surely, 2^{21012202021021} is an apocalyptic number.

It is an amenable number.

21012202021021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21012202021021 is an equidigital number, since it uses as much as digits as its factorization.

21012202021021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21012202021021 its reverse (12012020221012), we get a palindrome (33024222242033).

The spelling of 21012202021021 in words is "twenty-one trillion, twelve billion, two hundred two million, twenty-one thousand, twenty-one".