2165456161 has 4 divisors (see below), whose sum is σ = 2362315824. Its totient is φ = 1968596500.

The previous prime is 2165456143. The next prime is 2165456273. The reversal of 2165456161 is 1616545612.

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-2165456161 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a self number, because there is not a number n which added to its sum of digits gives 2165456161.

It is not an unprimeable number, because it can be changed into a prime (2165456131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 98429815 + ... + 98429836.

It is an arithmetic number, because the mean of its divisors is an integer number (590578956).

Almost surely, 2^2165456161 is an apocalyptic number.

It is an amenable number.

2165456161 is a deficient number, since it is larger than the sum of its proper divisors (196859663).

2165456161 is a wasteful number, since it uses less digits than its factorization.

2165456161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 196859662.

The product of its digits is 43200, while the sum is 37.

The square root of 2165456161 is about 46534.4620791946. The cubic root of 2165456161 is about 1293.7483194576.

It can be divided in two parts, 21654 and 56161, that added together give a triangular number (77815 = T₃₉₄).

The spelling of 2165456161 in words is "two billion, one hundred sixty-five million, four hundred fifty-six thousand, one hundred sixty-one".