16521665505 has 32 divisors (see below), whose sum is σ = 26873323776. Its totient is φ = 8666025984.

The previous prime is 16521665473. The next prime is 16521665527. The reversal of 16521665505 is 50556612561.

It is not a de Polignac number, because 16521665505 - 2⁵ = 16521665473 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 365164 + ... + 407906.

It is an arithmetic number, because the mean of its divisors is an integer number (839791368).

Almost surely, 2^16521665505 is an apocalyptic number.

16521665505 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

16521665505 is a deficient number, since it is larger than the sum of its proper divisors (10351658271).

16521665505 is a wasteful number, since it uses less digits than its factorization.

16521665505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43177.

The product of its (nonzero) digits is 270000, while the sum is 42.

The spelling of 16521665505 in words is "sixteen billion, five hundred twenty-one million, six hundred sixty-five thousand, five hundred five".