21002210209 has 2 divisors, whose sum is σ = 21002210210. Its totient is φ = 21002210208.

The previous prime is 21002210197. The next prime is 21002210213. The reversal of 21002210209 is 90201220012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20220840000 + 781370209 = 142200^2 + 27953^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21002210209 is a prime.

It is not a weakly prime, because it can be changed into another prime (21002210249) 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, 10501105104 + 10501105105.

It is an arithmetic number, because the mean of its divisors is an integer number (10501105105).

Almost surely, 2^21002210209 is an apocalyptic number.

It is an amenable number.

21002210209 is a deficient number, since it is larger than the sum of its proper divisors (1).

21002210209 is an equidigital number, since it uses as much as digits as its factorization.

21002210209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 144, while the sum is 19.

The spelling of 21002210209 in words is "twenty-one billion, two million, two hundred ten thousand, two hundred nine".