21013412009 has 2 divisors, whose sum is σ = 21013412010. Its totient is φ = 21013412008.

The previous prime is 21013411967. The next prime is 21013412011. The reversal of 21013412009 is 90021431012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20872158784 + 141253225 = 144472^2 + 11885^2 .

It is a cyclic number.

It is not a de Polignac number, because 21013412009 - 2⁸ = 21013411753 is a prime.

Together with 21013412011, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21013412029) 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, 10506706004 + 10506706005.

It is an arithmetic number, because the mean of its divisors is an integer number (10506706005).

Almost surely, 2^21013412009 is an apocalyptic number.

It is an amenable number.

21013412009 is a deficient number, since it is larger than the sum of its proper divisors (1).

21013412009 is an equidigital number, since it uses as much as digits as its factorization.

21013412009 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 23.

The spelling of 21013412009 in words is "twenty-one billion, thirteen million, four hundred twelve thousand, nine".