16505210521 has 8 divisors (see below), whose sum is σ = 16530263360. Its totient is φ = 16480178352.

The previous prime is 16505210503. The next prime is 16505210549. The reversal of 16505210521 is 12501250561.

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

It is a cyclic number.

It is not a de Polignac number, because 16505210521 - 2⁵ = 16505210489 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 16505210521.

It is not an unprimeable number, because it can be changed into a prime (16505210581) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 2301940 + ... + 2309098.

It is an arithmetic number, because the mean of its divisors is an integer number (2066282920).

Almost surely, 2^16505210521 is an apocalyptic number.

It is an amenable number.

16505210521 is a deficient number, since it is larger than the sum of its proper divisors (25052839).

16505210521 is a wasteful number, since it uses less digits than its factorization.

16505210521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10335.

The product of its (nonzero) digits is 3000, while the sum is 28.

The spelling of 16505210521 in words is "sixteen billion, five hundred five million, two hundred ten thousand, five hundred twenty-one".