216865539 has 16 divisors (see below), whose sum is σ = 350490240. Its totient is φ = 131433480.

The previous prime is 216865529. The next prime is 216865543. The reversal of 216865539 is 935568612.

216865539 is a `hidden beast` number, since 2 + 16 + 86 + 553 + 9 = 666.

216865539 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 216865539 - 2¹⁵ = 216832771 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 216865494 and 216865503.

It is not an unprimeable number, because it can be changed into a prime (216865529) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 364797 + ... + 365390.

It is an arithmetic number, because the mean of its divisors is an integer number (21905640).

Almost surely, 2^216865539 is an apocalyptic number.

216865539 is a deficient number, since it is larger than the sum of its proper divisors (133624701).

216865539 is a wasteful number, since it uses less digits than its factorization.

216865539 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 730207 (or 730201 counting only the distinct ones).

The product of its digits is 388800, while the sum is 45.

The square root of 216865539 is about 14726.3552517247. The cubic root of 216865539 is about 600.8003569067.

It can be divided in two parts, 21686 and 5539, that added together give a square (27225 = 165²).

The spelling of 216865539 in words is "two hundred sixteen million, eight hundred sixty-five thousand, five hundred thirty-nine".