216387985 has 16 divisors (see below), whose sum is σ = 299935872. Its totient is φ = 148115200.

The previous prime is 216387961. The next prime is 216387989. The reversal of 216387985 is 589783612.

216387985 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 216387985 - 2¹¹ = 216385937 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216387989) 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, 114781 + ... + 116650.

It is an arithmetic number, because the mean of its divisors is an integer number (18745992).

Almost surely, 2^216387985 is an apocalyptic number.

It is an amenable number.

216387985 is a deficient number, since it is larger than the sum of its proper divisors (83547887).

216387985 is a wasteful number, since it uses less digits than its factorization.

216387985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 231464.

The product of its digits is 725760, while the sum is 49.

The square root of 216387985 is about 14710.1320524324. The cubic root of 216387985 is about 600.3590304894.

The spelling of 216387985 in words is "two hundred sixteen million, three hundred eighty-seven thousand, nine hundred eighty-five".