216612161 has 4 divisors (see below), whose sum is σ = 217178112. Its totient is φ = 216046212.

The previous prime is 216612133. The next prime is 216612169. The reversal of 216612161 is 161216612.

216612161 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 a de Polignac number, because none of the positive numbers 2^k-216612161 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 216612161.

It is not an unprimeable number, because it can be changed into a prime (216612169) 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, 282401 + ... + 283166.

It is an arithmetic number, because the mean of its divisors is an integer number (54294528).

Almost surely, 2^216612161 is an apocalyptic number.

It is an amenable number.

216612161 is a deficient number, since it is larger than the sum of its proper divisors (565951).

216612161 is an equidigital number, since it uses as much as digits as its factorization.

216612161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 565950.

The product of its digits is 864, while the sum is 26.

The square root of 216612161 is about 14717.7498619864. The cubic root of 216612161 is about 600.5662811154.

Adding to 216612161 its reverse (161216612), we get a palindrome (377828773).

The spelling of 216612161 in words is "two hundred sixteen million, six hundred twelve thousand, one hundred sixty-one".