21043028305 has 8 divisors (see below), whose sum is σ = 27194067432. Its totient is φ = 15539467008.

The previous prime is 21043028269. The next prime is 21043028311. The reversal of 21043028305 is 50382034012.

It can be written as a sum of positive squares in 4 ways, for example, as 65561409 + 20977466896 = 8097^2 + 144836^2 .

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

It is not a de Polignac number, because 21043028305 - 2²⁷ = 20908810577 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 161869384 + ... + 161869513.

It is an arithmetic number, because the mean of its divisors is an integer number (3399258429).

Almost surely, 2^21043028305 is an apocalyptic number.

It is an amenable number.

21043028305 is a deficient number, since it is larger than the sum of its proper divisors (6151039127).

21043028305 is a wasteful number, since it uses less digits than its factorization.

21043028305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 323738915.

The product of its (nonzero) digits is 5760, while the sum is 28.

The spelling of 21043028305 in words is "twenty-one billion, forty-three million, twenty-eight thousand, three hundred five".