9865840 has 20 divisors (see below), whose sum is σ = 22938264. Its totient is φ = 3946304.

The previous prime is 9865837. The next prime is 9865841. The reversal of 9865840 is 485689.

It is a tau number, because it is divible by the number of its divisors (20).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 9865793 and 9865802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9865841) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 61582 + ... + 61741.

Almost surely, 2^9865840 is an apocalyptic number.

It is an amenable number.

9865840 is an abundant number, since it is smaller than the sum of its proper divisors (13072424).

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

9865840 is a wasteful number, since it uses less digits than its factorization.

9865840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123336 (or 123330 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 40.

The square root of 9865840 is about 3140.9934734093. The cubic root of 9865840 is about 214.4756647988.

The spelling of 9865840 in words is "nine million, eight hundred sixty-five thousand, eight hundred forty".