3865840 has 80 divisors (see below), whose sum is σ = 10285056. Its totient is φ = 1337600.

The previous prime is 3865819. The next prime is 3865847. The reversal of 3865840 is 485683.

3865840 is digitally balanced in base 5, because in such base it contains all the possibile digits an equal number of times.

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 = 3865796 and 3865805.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3865847) 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, 20145 + ... + 20335.

Almost surely, 2^3865840 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 3865840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (5142528).

3865840 is an abundant number, since it is smaller than the sum of its proper divisors (6419216).

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

3865840 is a wasteful number, since it uses less digits than its factorization.

3865840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 238 (or 232 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 34.

The square root of 3865840 is about 1966.1739495782. The cubic root of 3865840 is about 156.9451713288.

It can be divided in two parts, 386 and 5840, that added together give a palindrome (6226).

The spelling of 3865840 in words is "three million, eight hundred sixty-five thousand, eight hundred forty".