21212100002009 has 12 divisors (see below), whose sum is σ = 24705137171664. Its totient is φ = 18159814719144.

The previous prime is 21212100001979. The next prime is 21212100002047. The reversal of 21212100002009 is 90020000121212.

It is a happy number.

It is not a de Polignac number, because 21212100002009 - 2⁴⁰ = 20112588374233 is a prime.

It is a super-3 number, since 3×21212100002009³ (a number of 41 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21212100002089) 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 in 11 ways as a sum of consecutive naturals, for example, 261688619 + ... + 261769664.

It is an arithmetic number, because the mean of its divisors is an integer number (2058761430972).

Almost surely, 2^{21212100002009} is an apocalyptic number.

It is an amenable number.

21212100002009 is a deficient number, since it is larger than the sum of its proper divisors (3493037169655).

21212100002009 is an equidigital number, since it uses as much as digits as its factorization.

21212100002009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 523459124 (or 523459117 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 20.

The spelling of 21212100002009 in words is "twenty-one trillion, two hundred twelve billion, one hundred million, two thousand, nine".