21203000009 has 2 divisors, whose sum is σ = 21203000010. Its totient is φ = 21203000008.

The previous prime is 21203000003. The next prime is 21203000017. The reversal of 21203000009 is 90000030212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13889329609 + 7313670400 = 117853^2 + 85520^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21203000009 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21203000003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10601500004 + 10601500005.

It is an arithmetic number, because the mean of its divisors is an integer number (10601500005).

Almost surely, 2^21203000009 is an apocalyptic number.

It is an amenable number.

21203000009 is a deficient number, since it is larger than the sum of its proper divisors (1).

21203000009 is an equidigital number, since it uses as much as digits as its factorization.

21203000009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 108, while the sum is 17.

The spelling of 21203000009 in words is "twenty-one billion, two hundred three million, nine", and thus it is an aban number.