2165561420 has 96 divisors (see below), whose sum is σ = 5142638592. Its totient is φ = 758880000.

The previous prime is 2165561353. The next prime is 2165561441. The reversal of 2165561420 is 241655612.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2120510 + ... + 2121530.

It is an arithmetic number, because the mean of its divisors is an integer number (53569152).

Almost surely, 2^2165561420 is an apocalyptic number.

2165561420 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 2165561420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2571319296).

2165561420 is an abundant number, since it is smaller than the sum of its proper divisors (2977077172).

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

2165561420 is a wasteful number, since it uses less digits than its factorization.

2165561420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1383 (or 1381 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 32.

The square root of 2165561420 is about 46535.5930444644. The cubic root of 2165561420 is about 1293.7692813917.

The spelling of 2165561420 in words is "two billion, one hundred sixty-five million, five hundred sixty-one thousand, four hundred twenty".