21212021102021 has 2 divisors, whose sum is σ = 21212021102022. Its totient is φ = 21212021102020.

The previous prime is 21212021101963. The next prime is 21212021102057. The reversal of 21212021102021 is 12020112021212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19434828165025 + 1777192936996 = 4408495^2 + 1333114^2 .

It is a cyclic number.

It is not a de Polignac number, because 21212021102021 - 2²⁶ = 21211953993157 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21212021102071) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606010551010 + 10606010551011.

It is an arithmetic number, because the mean of its divisors is an integer number (10606010551011).

Almost surely, 2^{21212021102021} is an apocalyptic number.

It is an amenable number.

21212021102021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21212021102021 is an equidigital number, since it uses as much as digits as its factorization.

21212021102021 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 21212021102021 its reverse (12020112021212), we get a palindrome (33232133123233).

It can be divided in two parts, 2121202 and 1102021, that added together give a palindrome (3223223).

The spelling of 21212021102021 in words is "twenty-one trillion, two hundred twelve billion, twenty-one million, one hundred two thousand, twenty-one".