2165943780 has 384 divisors, whose sum is σ = 9049743360. Its totient is φ = 415342080.

The previous prime is 2165943763. The next prime is 2165943781. The reversal of 2165943780 is 873495612.

2165943780 is a `hidden beast` number, since 21 + 6 + 594 + 37 + 8 + 0 = 666.

2165943780 is digitally balanced in base 10, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (45).

2165943780 is strictly pandigital in base 10.

It is not an unprimeable number, because it can be changed into a prime (2165943781) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 538537 + ... + 542543.

It is an arithmetic number, because the mean of its divisors is an integer number (23567040).

It is a 1-persistent number, because it is pandigital, but 2⋅2165943780 = 4331887560 is not.

Almost surely, 2^2165943780 is an apocalyptic number.

2165943780 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 2165943780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4524871680).

2165943780 is an abundant number, since it is smaller than the sum of its proper divisors (6883799580).

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

2165943780 is a wasteful number, since it uses less digits than its factorization.

2165943780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4056 (or 4048 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 45.

The square root of 2165943780 is about 46539.7011163587. The cubic root of 2165943780 is about 1293.8454212334.

The spelling of 2165943780 in words is "two billion, one hundred sixty-five million, nine hundred forty-three thousand, seven hundred eighty".