21443205321 has 12 divisors (see below), whose sum is σ = 30976208640. Its totient is φ = 14294228760.

The previous prime is 21443205313. The next prime is 21443205359. The reversal of 21443205321 is 12350234412.

21443205321 is a `hidden beast` number, since 2 + 14 + 4 + 320 + 5 + 321 = 666.

It is not a de Polignac number, because 21443205321 - 2³ = 21443205313 is a prime.

It is a super-2 number, since 2×21443205321² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21443205361) 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 11 ways as a sum of consecutive naturals, for example, 12816 + ... + 207486.

It is an arithmetic number, because the mean of its divisors is an integer number (2581350720).

Almost surely, 2^21443205321 is an apocalyptic number.

It is an amenable number.

21443205321 is a deficient number, since it is larger than the sum of its proper divisors (9533003319).

21443205321 is a wasteful number, since it uses less digits than its factorization.

21443205321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 206916 (or 206913 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 27.

Adding to 21443205321 its reverse (12350234412), we get a palindrome (33793439733).

The spelling of 21443205321 in words is "twenty-one billion, four hundred forty-three million, two hundred five thousand, three hundred twenty-one".