21424203305 has 4 divisors (see below), whose sum is σ = 25709043972. Its totient is φ = 17139362640.

The previous prime is 21424203289. The next prime is 21424203377. The reversal of 21424203305 is 50330242412.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2441150464 + 18983052841 = 49408^2 + 137779^2 .

It is not a de Polignac number, because 21424203305 - 2⁴ = 21424203289 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2142420326 + ... + 2142420335.

It is an arithmetic number, because the mean of its divisors is an integer number (6427260993).

Almost surely, 2^21424203305 is an apocalyptic number.

It is an amenable number.

21424203305 is a deficient number, since it is larger than the sum of its proper divisors (4284840667).

21424203305 is an equidigital number, since it uses as much as digits as its factorization.

21424203305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4284840666.

The product of its (nonzero) digits is 5760, while the sum is 26.

Adding to 21424203305 its reverse (50330242412), we get a palindrome (71754445717).

The spelling of 21424203305 in words is "twenty-one billion, four hundred twenty-four million, two hundred three thousand, three hundred five".