216161609 has 4 divisors (see below), whose sum is σ = 216511440. Its totient is φ = 215811780.

The previous prime is 216161587. The next prime is 216161623. The reversal of 216161609 is 906161612.

216161609 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 216161609 - 2⁸ = 216161353 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (216161669) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 173987 + ... + 175224.

It is an arithmetic number, because the mean of its divisors is an integer number (54127860).

Almost surely, 2^216161609 is an apocalyptic number.

It is an amenable number.

216161609 is a deficient number, since it is larger than the sum of its proper divisors (349831).

216161609 is an equidigital number, since it uses as much as digits as its factorization.

216161609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 349830.

The product of its (nonzero) digits is 3888, while the sum is 32.

The square root of 216161609 is about 14702.4354785185. The cubic root of 216161609 is about 600.1496006593.

The spelling of 216161609 in words is "two hundred sixteen million, one hundred sixty-one thousand, six hundred nine".