216505551621517 has 16 divisors (see below), whose sum is σ = 225003775334400. Its totient is φ = 208102141814400.

The previous prime is 216505551621481. The next prime is 216505551621529. The reversal of 216505551621517 is 715126155505612.

It is a cyclic number.

It is not a de Polignac number, because 216505551621517 - 2¹⁹ = 216505551097229 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216505551621577) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 71878588 + ... + 74830090.

It is an arithmetic number, because the mean of its divisors is an integer number (14062735958400).

Almost surely, 2^{216505551621517} is an apocalyptic number.

It is an amenable number.

216505551621517 is a deficient number, since it is larger than the sum of its proper divisors (8498223712883).

216505551621517 is a wasteful number, since it uses less digits than its factorization.

216505551621517 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2967564.

The product of its (nonzero) digits is 3150000, while the sum is 52.

The spelling of 216505551621517 in words is "two hundred sixteen trillion, five hundred five billion, five hundred fifty-one million, six hundred twenty-one thousand, five hundred seventeen".