21203302009 has 2 divisors, whose sum is σ = 21203302010. Its totient is φ = 21203302008.

The previous prime is 21203301991. The next prime is 21203302019. The reversal of 21203302009 is 90020330212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18566787600 + 2636514409 = 136260^2 + 51347^2 .

It is a cyclic number.

It is not a de Polignac number, because 21203302009 - 2³¹ = 19055818361 is a prime.

It is not a weakly prime, because it can be changed into another prime (21203302019) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10601651004 + 10601651005.

It is an arithmetic number, because the mean of its divisors is an integer number (10601651005).

Almost surely, 2^21203302009 is an apocalyptic number.

It is an amenable number.

21203302009 is a deficient number, since it is larger than the sum of its proper divisors (1).

21203302009 is an equidigital number, since it uses as much as digits as its factorization.

21203302009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 648, while the sum is 22.

The spelling of 21203302009 in words is "twenty-one billion, two hundred three million, three hundred two thousand, nine".