2161805760 has 224 divisors, whose sum is σ = 7723022400. Its totient is φ = 576294912.

The previous prime is 2161805741. The next prime is 2161805777. The reversal of 2161805760 is 675081612.

2161805760 is a `hidden beast` number, since 2 + 1 + 6 + 1 + 80 + 576 + 0 = 666.

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

It is a congruent number.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 698296 + ... + 701384.

Almost surely, 2^2161805760 is an apocalyptic number.

2161805760 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 2161805760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3861511200).

2161805760 is an abundant number, since it is smaller than the sum of its proper divisors (5561216640).

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

2161805760 is an frugal number, since it uses more digits than its factorization.

2161805760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3127 (or 3099 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 36.

The square root of 2161805760 is about 46495.2229804310. Note that the first 3 decimals coincide. The cubic root of 2161805760 is about 1293.0209351642.

The spelling of 2161805760 in words is "two billion, one hundred sixty-one million, eight hundred five thousand, seven hundred sixty".