216855785 has 8 divisors (see below), whose sum is σ = 260351496. Its totient is φ = 173401600.

The previous prime is 216855763. The next prime is 216855803. The reversal of 216855785 is 587558612.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 3345241 + 213510544 = 1829^2 + 14612^2 .

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

It is not a de Polignac number, because 216855785 - 2¹² = 216851689 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 (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2585 + ... + 20985.

It is an arithmetic number, because the mean of its divisors is an integer number (32543937).

Almost surely, 2^216855785 is an apocalyptic number.

It is an amenable number.

216855785 is a deficient number, since it is larger than the sum of its proper divisors (43495711).

216855785 is a wasteful number, since it uses less digits than its factorization.

216855785 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20763.

The product of its digits is 672000, while the sum is 47.

The square root of 216855785 is about 14726.0240730484. The cubic root of 216855785 is about 600.7913493367.

The spelling of 216855785 in words is "two hundred sixteen million, eight hundred fifty-five thousand, seven hundred eighty-five".