216516785 has 8 divisors (see below), whose sum is σ = 266842536. Its totient is φ = 168531840.

The previous prime is 216516767. The next prime is 216516787. The reversal of 216516785 is 587615612.

It can be written as a sum of positive squares in 4 ways, for example, as 94789696 + 121727089 = 9736^2 + 11033^2 .

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

It is not a de Polignac number, because 216516785 - 2⁸ = 216516529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216516787) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 584996 + ... + 585365.

It is an arithmetic number, because the mean of its divisors is an integer number (33355317).

Almost surely, 2^216516785 is an apocalyptic number.

It is an amenable number.

216516785 is a deficient number, since it is larger than the sum of its proper divisors (50325751).

216516785 is a wasteful number, since it uses less digits than its factorization.

216516785 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1170403.

The product of its digits is 100800, while the sum is 41.

The square root of 216516785 is about 14714.5093360261. The cubic root of 216516785 is about 600.4781235249.

The spelling of 216516785 in words is "two hundred sixteen million, five hundred sixteen thousand, seven hundred eighty-five".