2161618816 has 128 divisors (see below), whose sum is σ = 5245378560. Its totient is φ = 866181120.

The previous prime is 2161618793. The next prime is 2161618819. The reversal of 2161618816 is 6188161612.

It is a tau number, because it is divible by the number of its divisors (128).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2161618819) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2908941 + ... + 2909683.

It is an arithmetic number, because the mean of its divisors is an integer number (40979520).

Almost surely, 2^2161618816 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 2161618816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2622689280).

2161618816 is an abundant number, since it is smaller than the sum of its proper divisors (3083759744).

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

2161618816 is a wasteful number, since it uses less digits than its factorization.

2161618816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 972 (or 960 counting only the distinct ones).

The product of its digits is 27648, while the sum is 40.

The square root of 2161618816 is about 46493.2125799025. The cubic root of 2161618816 is about 1292.9836623931.

The spelling of 2161618816 in words is "two billion, one hundred sixty-one million, six hundred eighteen thousand, eight hundred sixteen".