216078865 has 4 divisors (see below), whose sum is σ = 259294644. Its totient is φ = 172863088.

The previous prime is 216078829. The next prime is 216078883. The reversal of 216078865 is 568870612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 89718784 + 126360081 = 9472^2 + 11241^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216078865 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21607882 + ... + 21607891.

It is an arithmetic number, because the mean of its divisors is an integer number (64823661).

Almost surely, 2^216078865 is an apocalyptic number.

It is an amenable number.

216078865 is a deficient number, since it is larger than the sum of its proper divisors (43215779).

216078865 is an equidigital number, since it uses as much as digits as its factorization.

216078865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43215778.

The product of its (nonzero) digits is 161280, while the sum is 43.

The square root of 216078865 is about 14699.6212536242. The cubic root of 216078865 is about 600.0730142627.

The spelling of 216078865 in words is "two hundred sixteen million, seventy-eight thousand, eight hundred sixty-five".