16543522321 has 4 divisors (see below), whose sum is σ = 16543922544. Its totient is φ = 16543122100.

The previous prime is 16543522313. The next prime is 16543522417. The reversal of 16543522321 is 12322534561.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 16543522321 - 2³ = 16543522313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16543522301) 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, 129895 + ... + 223516.

It is an arithmetic number, because the mean of its divisors is an integer number (4135980636).

Almost surely, 2^16543522321 is an apocalyptic number.

It is an amenable number.

16543522321 is a deficient number, since it is larger than the sum of its proper divisors (400223).

16543522321 is an equidigital number, since it uses as much as digits as its factorization.

16543522321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 400222.

The product of its digits is 43200, while the sum is 34.

The spelling of 16543522321 in words is "sixteen billion, five hundred forty-three million, five hundred twenty-two thousand, three hundred twenty-one".