2165821056 has 192 divisors, whose sum is σ = 7150852800. Its totient is φ = 616366080.

The previous prime is 2165821037. The next prime is 2165821079. The reversal of 2165821056 is 6501285612.

2165821056 is a `hidden beast` number, since 2 + 16 + 582 + 10 + 56 = 666.

It is a tau number, because it is divible by the number of its divisors (192).

It is a super-2 number, since 2×2165821056² = 9381561693225910272, which contains 22 as substring.

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 2165821056.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3378496 + ... + 3379136.

It is an arithmetic number, because the mean of its divisors is an integer number (37244025).

Almost surely, 2^2165821056 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 2165821056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3575426400).

2165821056 is an abundant number, since it is smaller than the sum of its proper divisors (4985031744).

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

2165821056 is a wasteful number, since it uses less digits than its factorization.

2165821056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1087 (or 1072 counting only the distinct ones).

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

The square root of 2165821056 is about 46538.3826104862. The cubic root of 2165821056 is about 1293.8209840210.

The spelling of 2165821056 in words is "two billion, one hundred sixty-five million, eight hundred twenty-one thousand, fifty-six".