16506161321 has 4 divisors (see below), whose sum is σ = 17775866052. Its totient is φ = 15236456592.

The previous prime is 16506161311. The next prime is 16506161323. The reversal of 16506161321 is 12316160561.

16506161321 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1884514921 + 14621646400 = 43411^2 + 120920^2 .

It is a cyclic number.

It is not a de Polignac number, because 16506161321 - 2²² = 16501967017 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16506161323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 634852346 + ... + 634852371.

It is an arithmetic number, because the mean of its divisors is an integer number (4443966513).

Almost surely, 2^16506161321 is an apocalyptic number.

It is an amenable number.

16506161321 is a deficient number, since it is larger than the sum of its proper divisors (1269704731).

16506161321 is a wasteful number, since it uses less digits than its factorization.

16506161321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1269704730.

The product of its (nonzero) digits is 6480, while the sum is 32.

The spelling of 16506161321 in words is "sixteen billion, five hundred six million, one hundred sixty-one thousand, three hundred twenty-one".