21000000002221 has 2 divisors, whose sum is σ = 21000000002222. Its totient is φ = 21000000002220.

The previous prime is 21000000002203. The next prime is 21000000002237. The reversal of 21000000002221 is 12220000000012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20956710622500 + 43289379721 = 4577850^2 + 208061^2 .

It is a cyclic number.

It is not a de Polignac number, because 21000000002221 - 2¹¹ = 21000000000173 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21000000002198 and 21000000002207.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21000000302221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500000001110 + 10500000001111.

It is an arithmetic number, because the mean of its divisors is an integer number (10500000001111).

Almost surely, 2^{21000000002221} is an apocalyptic number.

It is an amenable number.

21000000002221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000000002221 is an equidigital number, since it uses as much as digits as its factorization.

21000000002221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16, while the sum is 10.

Adding to 21000000002221 its reverse (12220000000012), we get a palindrome (33220000002233).

The spelling of 21000000002221 in words is "twenty-one trillion, two thousand, two hundred twenty-one".