16806928321 has 4 divisors (see below), whose sum is σ = 17216853444. Its totient is φ = 16397003200.

The previous prime is 16806928319. The next prime is 16806928381. The reversal of 16806928321 is 12382960861.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12382960861 = 4241 ⋅2919821.

It can be written as a sum of positive squares in 2 ways, for example, as 8753660721 + 8053267600 = 93561^2 + 89740^2 .

It is a cyclic number.

It is not a de Polignac number, because 16806928321 - 2¹ = 16806928319 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16806928381) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 204962500 + ... + 204962581.

It is an arithmetic number, because the mean of its divisors is an integer number (4304213361).

Almost surely, 2^16806928321 is an apocalyptic number.

It is an amenable number.

16806928321 is a deficient number, since it is larger than the sum of its proper divisors (409925123).

16806928321 is an equidigital number, since it uses as much as digits as its factorization.

16806928321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 409925122.

The product of its (nonzero) digits is 248832, while the sum is 46.

The spelling of 16806928321 in words is "sixteen billion, eight hundred six million, nine hundred twenty-eight thousand, three hundred twenty-one".