21240413500309 has 2 divisors, whose sum is σ = 21240413500310. Its totient is φ = 21240413500308.

The previous prime is 21240413500307. The next prime is 21240413500351. The reversal of 21240413500309 is 90300531404212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20696585422500 + 543828077809 = 4549350^2 + 737447^2 .

It is a cyclic number.

It is not a de Polignac number, because 21240413500309 - 2¹ = 21240413500307 is a prime.

Together with 21240413500307, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21240413500307) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10620206750154 + 10620206750155.

It is an arithmetic number, because the mean of its divisors is an integer number (10620206750155).

Almost surely, 2^{21240413500309} is an apocalyptic number.

It is an amenable number.

21240413500309 is a deficient number, since it is larger than the sum of its proper divisors (1).

21240413500309 is an equidigital number, since it uses as much as digits as its factorization.

21240413500309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25920, while the sum is 34.

The spelling of 21240413500309 in words is "twenty-one trillion, two hundred forty billion, four hundred thirteen million, five hundred thousand, three hundred nine".