21112010209 has 2 divisors, whose sum is σ = 21112010210. Its totient is φ = 21112010208.

The previous prime is 21112010207. The next prime is 21112010233. The reversal of 21112010209 is 90201021112.

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., 20285735184 + 826275025 = 142428^2 + 28745^2 .

It is a cyclic number.

It is not a de Polignac number, because 21112010209 - 2¹ = 21112010207 is a prime.

Together with 21112010207, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21112010207) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10556005104 + 10556005105.

It is an arithmetic number, because the mean of its divisors is an integer number (10556005105).

Almost surely, 2^21112010209 is an apocalyptic number.

It is an amenable number.

21112010209 is a deficient number, since it is larger than the sum of its proper divisors (1).

21112010209 is an equidigital number, since it uses as much as digits as its factorization.

21112010209 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 21112010209 in words is "twenty-one billion, one hundred twelve million, ten thousand, two hundred nine".