216856870517 has 32 divisors (see below), whose sum is σ = 264269101824. Its totient is φ = 173710310400.

The previous prime is 216856870511. The next prime is 216856870583. The reversal of 216856870517 is 715078658612.

It is a cyclic number.

It is not a de Polignac number, because 216856870517 - 2¹⁴ = 216856854133 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216856870511) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 14703767 + ... + 14718507.

It is an arithmetic number, because the mean of its divisors is an integer number (8258409432).

Almost surely, 2^216856870517 is an apocalyptic number.

It is an amenable number.

216856870517 is a deficient number, since it is larger than the sum of its proper divisors (47412231307).

216856870517 is a wasteful number, since it uses less digits than its factorization.

216856870517 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15629.

The product of its (nonzero) digits is 5644800, while the sum is 56.

The spelling of 216856870517 in words is "two hundred sixteen billion, eight hundred fifty-six million, eight hundred seventy thousand, five hundred seventeen".