21120211220209 has 2 divisors, whose sum is σ = 21120211220210. Its totient is φ = 21120211220208.

The previous prime is 21120211220177. The next prime is 21120211220231. The reversal of 21120211220209 is 90202211202112.

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., 15472839203809 + 5647372016400 = 3933553^2 + 2376420^2 .

It is a cyclic number.

It is not a de Polignac number, because 21120211220209 - 2⁵ = 21120211220177 is a prime.

It is not a weakly prime, because it can be changed into another prime (21120211220239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560105610104 + 10560105610105.

It is an arithmetic number, because the mean of its divisors is an integer number (10560105610105).

Almost surely, 2^{21120211220209} is an apocalyptic number.

It is an amenable number.

21120211220209 is a deficient number, since it is larger than the sum of its proper divisors (1).

21120211220209 is an equidigital number, since it uses as much as digits as its factorization.

21120211220209 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 21120211220209 in words is "twenty-one trillion, one hundred twenty billion, two hundred eleven million, two hundred twenty thousand, two hundred nine".