2166055820 has 96 divisors (see below), whose sum is σ = 4934563200. Its totient is φ = 796207104.

The previous prime is 2166055807. The next prime is 2166055831. The reversal of 2166055820 is 285506612.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5295776 + ... + 5296184.

It is an arithmetic number, because the mean of its divisors is an integer number (51401700).

Almost surely, 2^2166055820 is an apocalyptic number.

2166055820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2166055820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2467281600).

2166055820 is an abundant number, since it is smaller than the sum of its proper divisors (2768507380).

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

2166055820 is a wasteful number, since it uses less digits than its factorization.

2166055820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 867 (or 865 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 35.

The square root of 2166055820 is about 46540.9048042687. The cubic root of 2166055820 is about 1293.8677302060.

The spelling of 2166055820 in words is "two billion, one hundred sixty-six million, fifty-five thousand, eight hundred twenty".