21221110021021 has 2 divisors, whose sum is σ = 21221110021022. Its totient is φ = 21221110021020.

The previous prime is 21221110020941. The next prime is 21221110021031. The reversal of 21221110021021 is 12012001112212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19467111744025 + 1753998276996 = 4412155^2 + 1324386^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221110021021 - 2¹⁷ = 21221109889949 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21221110020986 and 21221110021004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21221110021031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610555010510 + 10610555010511.

It is an arithmetic number, because the mean of its divisors is an integer number (10610555010511).

Almost surely, 2^{21221110021021} is an apocalyptic number.

It is an amenable number.

21221110021021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221110021021 is an equidigital number, since it uses as much as digits as its factorization.

21221110021021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 21221110021021 its reverse (12012001112212), we get a palindrome (33233111133233).

The spelling of 21221110021021 in words is "twenty-one trillion, two hundred twenty-one billion, one hundred ten million, twenty-one thousand, twenty-one".