21212203009 has 2 divisors, whose sum is σ = 21212203010. Its totient is φ = 21212203008.

The previous prime is 21212203007. The next prime is 21212203073. The reversal of 21212203009 is 90030221212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17754763009 + 3457440000 = 133247^2 + 58800^2 .

It is a cyclic number.

It is not a de Polignac number, because 21212203009 - 2¹ = 21212203007 is a prime.

Together with 21212203007, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21212203007) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606101504 + 10606101505.

It is an arithmetic number, because the mean of its divisors is an integer number (10606101505).

Almost surely, 2^21212203009 is an apocalyptic number.

It is an amenable number.

21212203009 is a deficient number, since it is larger than the sum of its proper divisors (1).

21212203009 is an equidigital number, since it uses as much as digits as its factorization.

21212203009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432, while the sum is 22.

The spelling of 21212203009 in words is "twenty-one billion, two hundred twelve million, two hundred three thousand, nine".