16561999996 has 24 divisors (see below), whose sum is σ = 29305766336. Its totient is φ = 8189061120.

The previous prime is 16561999939. The next prime is 16561999997. The reversal of 16561999996 is 69999916561.

16561999996 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16561999997) 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 7 ways as a sum of consecutive naturals, for example, 486781 + ... + 519691.

Almost surely, 2^16561999996 is an apocalyptic number.

It is an amenable number.

16561999996 is a deficient number, since it is larger than the sum of its proper divisors (12743766340).

16561999996 is a wasteful number, since it uses less digits than its factorization.

16561999996 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34309 (or 34307 counting only the distinct ones).

The product of its digits is 63772920, while the sum is 70.

The spelling of 16561999996 in words is "sixteen billion, five hundred sixty-one million, nine hundred ninety-nine thousand, nine hundred ninety-six".