21221222201 has 2 divisors, whose sum is σ = 21221222202. Its totient is φ = 21221222200.

The previous prime is 21221222171. The next prime is 21221222219. The reversal of 21221222201 is 10222212212.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18215551225 + 3005670976 = 134965^2 + 54824^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221222201 - 2⁶ = 21221222137 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21221222201.

It is not a weakly prime, because it can be changed into another prime (21221222221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610611100 + 10610611101.

It is an arithmetic number, because the mean of its divisors is an integer number (10610611101).

Almost surely, 2^21221222201 is an apocalyptic number.

It is an amenable number.

21221222201 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221222201 is an equidigital number, since it uses as much as digits as its factorization.

21221222201 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 21221222201 its reverse (10222212212), we get a palindrome (31443434413).

The spelling of 21221222201 in words is "twenty-one billion, two hundred twenty-one million, two hundred twenty-two thousand, two hundred one".