21221011022209 has 2 divisors, whose sum is σ = 21221011022210. Its totient is φ = 21221011022208.

The previous prime is 21221011022171. The next prime is 21221011022293. The reversal of 21221011022209 is 90222011012212.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11902003205184 + 9319007817025 = 3449928^2 + 3052705^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221011022209 - 2¹⁷ = 21221010891137 is a prime.

It is not a weakly prime, because it can be changed into another prime (21221011026209) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610505511104 + 10610505511105.

It is an arithmetic number, because the mean of its divisors is an integer number (10610505511105).

Almost surely, 2^{21221011022209} is an apocalyptic number.

It is an amenable number.

21221011022209 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221011022209 is an equidigital number, since it uses as much as digits as its factorization.

21221011022209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 25.

The spelling of 21221011022209 in words is "twenty-one trillion, two hundred twenty-one billion, eleven million, twenty-two thousand, two hundred nine".