1081844865 has 12 divisors (see below), whose sum is σ = 1875197844. Its totient is φ = 576983904.

The previous prime is 1081844833. The next prime is 1081844891. The reversal of 1081844865 is 5684481801.

1081844865 is a `hidden beast` number, since 10 + 81 + 84 + 486 + 5 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 510443649 + 571401216 = 22593^2 + 23904^2 .

It is not a de Polignac number, because 1081844865 - 2⁵ = 1081844833 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 24040997 = 1081844865 / (1 + 0 + 8 + 1 + 8 + 4 + 4 + 8 + 6 + 5).

It is a self number, because there is not a number n which added to its sum of digits gives 1081844865.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12020454 + ... + 12020543.

It is an arithmetic number, because the mean of its divisors is an integer number (156266487).

Almost surely, 2^1081844865 is an apocalyptic number.

1081844865 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1081844865 is a deficient number, since it is larger than the sum of its proper divisors (793352979).

1081844865 is a wasteful number, since it uses less digits than its factorization.

1081844865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24041008 (or 24041005 counting only the distinct ones).

The product of its (nonzero) digits is 245760, while the sum is 45.

The square root of 1081844865 is about 32891.4102008412. The cubic root of 1081844865 is about 1026.5694347092.

The spelling of 1081844865 in words is "one billion, eighty-one million, eight hundred forty-four thousand, eight hundred sixty-five".