2165218056 has 96 divisors (see below), whose sum is σ = 6231583800. Its totient is φ = 679173120.

The previous prime is 2165218037. The next prime is 2165218057. The reversal of 2165218056 is 6508125612.

2165218056 is a `hidden beast` number, since 2 + 1 + 6 + 521 + 80 + 56 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 1549681956 + 615536100 = 39366^2 + 24810^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 2165218056.

It is not an unprimeable number, because it can be changed into a prime (2165218057) 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 23 ways as a sum of consecutive naturals, for example, 350676 + ... + 356796.

Almost surely, 2^2165218056 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2165218056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3115791900).

2165218056 is an abundant number, since it is smaller than the sum of its proper divisors (4066365744).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

2165218056 is a wasteful number, since it uses less digits than its factorization.

2165218056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6184 (or 6143 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 36.

The square root of 2165218056 is about 46531.9036361076. The cubic root of 2165218056 is about 1293.7008992357.

The spelling of 2165218056 in words is "two billion, one hundred sixty-five million, two hundred eighteen thousand, fifty-six".