21212011202021 has 2 divisors, whose sum is σ = 21212011202022. Its totient is φ = 21212011202020.

The previous prime is 21212011201967. The next prime is 21212011202101. The reversal of 21212011202021 is 12020211021212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12427669584100 + 8784341617921 = 3525290^2 + 2963839^2 .

It is a cyclic number.

It is not a de Polignac number, because 21212011202021 - 2³⁴ = 21194831332837 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21212011102021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606005601010 + 10606005601011.

It is an arithmetic number, because the mean of its divisors is an integer number (10606005601011).

Almost surely, 2^{21212011202021} is an apocalyptic number.

It is an amenable number.

21212011202021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21212011202021 is an equidigital number, since it uses as much as digits as its factorization.

21212011202021 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 17.

Adding to 21212011202021 its reverse (12020211021212), we get a palindrome (33232222223233).

The spelling of 21212011202021 in words is "twenty-one trillion, two hundred twelve billion, eleven million, two hundred two thousand, twenty-one".