21305469413 has 2 divisors, whose sum is σ = 21305469414. Its totient is φ = 21305469412.

The previous prime is 21305469403. The next prime is 21305469431. The reversal of 21305469413 is 31496450312.

Together with next prime (21305469431) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17266485604 + 4038983809 = 131402^2 + 63553^2 .

It is a cyclic number.

It is not a de Polignac number, because 21305469413 - 2⁶ = 21305469349 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21305469403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10652734706 + 10652734707.

It is an arithmetic number, because the mean of its divisors is an integer number (10652734707).

Almost surely, 2^21305469413 is an apocalyptic number.

It is an amenable number.

21305469413 is a deficient number, since it is larger than the sum of its proper divisors (1).

21305469413 is an equidigital number, since it uses as much as digits as its factorization.

21305469413 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 77760, while the sum is 38.

The spelling of 21305469413 in words is "twenty-one billion, three hundred five million, four hundred sixty-nine thousand, four hundred thirteen".