21230021423 has 16 divisors (see below), whose sum is σ = 23060795520. Its totient is φ = 19428194304.

The previous prime is 21230021411. The next prime is 21230021429. The reversal of 21230021423 is 32412003212.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21230021423 is a prime.

It is a Duffinian number.

21230021423 is a modest number, since divided by 21423 gives 21230 as remainder.

It is a junction number, because it is equal to n+sod(n) for n = 21230021395 and 21230021404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21230021429) 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, 720698 + ... + 749576.

It is an arithmetic number, because the mean of its divisors is an integer number (1441299720).

Almost surely, 2^21230021423 is an apocalyptic number.

21230021423 is a deficient number, since it is larger than the sum of its proper divisors (1830774097).

21230021423 is a wasteful number, since it uses less digits than its factorization.

21230021423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29378.

The product of its (nonzero) digits is 576, while the sum is 20.

Adding to 21230021423 its reverse (32412003212), we get a palindrome (53642024635).

The spelling of 21230021423 in words is "twenty-one billion, two hundred thirty million, twenty-one thousand, four hundred twenty-three".