21004430321 has 8 divisors (see below), whose sum is σ = 24007866624. Its totient is φ = 18001694880.

The previous prime is 21004430311. The next prime is 21004430383. The reversal of 21004430321 is 12303440012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21004430321 - 2³⁴ = 3824561137 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21004430293 and 21004430302.

It is not an unprimeable number, because it can be changed into a prime (21004430311) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 109340 + ... + 232301.

It is an arithmetic number, because the mean of its divisors is an integer number (3000983328).

Almost surely, 2^21004430321 is an apocalyptic number.

It is an amenable number.

21004430321 is a deficient number, since it is larger than the sum of its proper divisors (3003436303).

21004430321 is an equidigital number, since it uses as much as digits as its factorization.

21004430321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 350431.

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

Adding to 21004430321 its reverse (12303440012), we get a palindrome (33307870333).

The spelling of 21004430321 in words is "twenty-one billion, four million, four hundred thirty thousand, three hundred twenty-one".