21243304423 has 16 divisors (see below), whose sum is σ = 23330246400. Its totient is φ = 19182458880.

The previous prime is 21243304417. The next prime is 21243304427. The reversal of 21243304423 is 32440334212.

It is a cyclic number.

It is not a de Polignac number, because 21243304423 - 2²⁹ = 20706433511 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21243304391 and 21243304400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21243304427) 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 in 15 ways as a sum of consecutive naturals, for example, 5967118 + ... + 5970676.

It is an arithmetic number, because the mean of its divisors is an integer number (1458140400).

Almost surely, 2^21243304423 is an apocalyptic number.

21243304423 is a deficient number, since it is larger than the sum of its proper divisors (2086941977).

21243304423 is a wasteful number, since it uses less digits than its factorization.

21243304423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7062.

The product of its (nonzero) digits is 13824, while the sum is 28.

Adding to 21243304423 its reverse (32440334212), we get a palindrome (53683638635).

The spelling of 21243304423 in words is "twenty-one billion, two hundred forty-three million, three hundred four thousand, four hundred twenty-three".