216865538 has 8 divisors (see below), whose sum is σ = 336515580. Its totient is φ = 104693680.

The previous prime is 216865529. The next prime is 216865543. The reversal of 216865538 is 835568612.

It can be written as a sum of positive squares in 2 ways, for example, as 192293689 + 24571849 = 13867^2 + 4957^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1869473 + ... + 1869588.

Almost surely, 2^216865538 is an apocalyptic number.

216865538 is a deficient number, since it is larger than the sum of its proper divisors (119650042).

216865538 is a wasteful number, since it uses less digits than its factorization.

216865538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3739092.

The product of its digits is 345600, while the sum is 44.

The square root of 216865538 is about 14726.3552177720. The cubic root of 216865538 is about 600.8003559832.

The spelling of 216865538 in words is "two hundred sixteen million, eight hundred sixty-five thousand, five hundred thirty-eight".