21210011002009 has 2 divisors, whose sum is σ = 21210011002010. Its totient is φ = 21210011002008.

The previous prime is 21210011001979. The next prime is 21210011002027. The reversal of 21210011002009 is 90020011001212.

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., 19364752291600 + 1845258710409 = 4400540^2 + 1358403^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21210011002009 is a prime.

It is not a weakly prime, because it can be changed into another prime (21210011002049) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605005501004 + 10605005501005.

It is an arithmetic number, because the mean of its divisors is an integer number (10605005501005).

Almost surely, 2^{21210011002009} is an apocalyptic number.

It is an amenable number.

21210011002009 is a deficient number, since it is larger than the sum of its proper divisors (1).

21210011002009 is an equidigital number, since it uses as much as digits as its factorization.

21210011002009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 19.

The spelling of 21210011002009 in words is "twenty-one trillion, two hundred ten billion, eleven million, two thousand, nine".