2161563440 has 80 divisors (see below), whose sum is σ = 5105753568. Its totient is φ = 850956288.

The previous prime is 2161563427. The next prime is 2161563449. The reversal of 2161563440 is 443651612.

It is a tau number, because it is divible by the number of its divisors (80).

It is a junction number, because it is equal to n+sod(n) for n = 2161563397 and 2161563406.

It is not an unprimeable number, because it can be changed into a prime (2161563449) 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, 1418519 + ... + 1420041.

Almost surely, 2^2161563440 is an apocalyptic number.

2161563440 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 2161563440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2552876784).

2161563440 is an abundant number, since it is smaller than the sum of its proper divisors (2944190128).

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

2161563440 is a wasteful number, since it uses less digits than its factorization.

2161563440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1806 (or 1800 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 32.

The square root of 2161563440 is about 46492.6170483013. The cubic root of 2161563440 is about 1292.9726211503.

The spelling of 2161563440 in words is "two billion, one hundred sixty-one million, five hundred sixty-three thousand, four hundred forty".