21202221122021 has 2 divisors, whose sum is σ = 21202221122022. Its totient is φ = 21202221122020.

The previous prime is 21202221121987. The next prime is 21202221122059. The reversal of 21202221122021 is 12022112220212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19281671388100 + 1920549733921 = 4391090^2 + 1385839^2 .

It is a cyclic number.

It is not a de Polignac number, because 21202221122021 - 2⁶ = 21202221121957 is a prime.

It is a super-2 number, since 2×21202221122021² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21202221121984 and 21202221122002.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21202221122921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10601110561010 + 10601110561011.

It is an arithmetic number, because the mean of its divisors is an integer number (10601110561011).

Almost surely, 2^{21202221122021} is an apocalyptic number.

It is an amenable number.

21202221122021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21202221122021 is an equidigital number, since it uses as much as digits as its factorization.

21202221122021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 256, while the sum is 20.

Adding to 21202221122021 its reverse (12022112220212), we get a palindrome (33224333342233).

The spelling of 21202221122021 in words is "twenty-one trillion, two hundred two billion, two hundred twenty-one million, one hundred twenty-two thousand, twenty-one".