16521665516 has 12 divisors (see below), whose sum is σ = 29909911920. Its totient is φ = 7975976400.

The previous prime is 16521665473. The next prime is 16521665527. The reversal of 16521665516 is 61556612561.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 71213960 + ... + 71214191.

It is an arithmetic number, because the mean of its divisors is an integer number (2492492660).

Almost surely, 2^16521665516 is an apocalyptic number.

It is an amenable number.

16521665516 is a deficient number, since it is larger than the sum of its proper divisors (13388246404).

16521665516 is a wasteful number, since it uses less digits than its factorization.

16521665516 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 142428184 (or 142428182 counting only the distinct ones).

The product of its digits is 324000, while the sum is 44.

The spelling of 16521665516 in words is "sixteen billion, five hundred twenty-one million, six hundred sixty-five thousand, five hundred sixteen".