16521665506 has 8 divisors (see below), whose sum is σ = 25309785600. Its totient is φ = 8085070308.

The previous prime is 16521665473. The next prime is 16521665527. The reversal of 16521665506 is 60556612561.

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 87881106 + ... + 87881293.

It is an arithmetic number, because the mean of its divisors is an integer number (3163723200).

Almost surely, 2^16521665506 is an apocalyptic number.

16521665506 is a deficient number, since it is larger than the sum of its proper divisors (8788120094).

16521665506 is a wasteful number, since it uses less digits than its factorization.

16521665506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 175762448.

The product of its (nonzero) digits is 324000, while the sum is 43.

The spelling of 16521665506 in words is "sixteen billion, five hundred twenty-one million, six hundred sixty-five thousand, five hundred six".