3865581 has 6 divisors (see below), whose sum is σ = 5583630. Its totient is φ = 2577048.

The previous prime is 3865577. The next prime is 3865591. The reversal of 3865581 is 1855683.

It can be written as a sum of positive squares in only one way, i.e., 3861225 + 4356 = 1965^2 + 66^2 .

It is not a de Polignac number, because 3865581 - 2² = 3865577 is a prime.

It is a super-2 number, since 2×3865581² = 29885432935122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3865591) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 214746 + ... + 214763.

It is an arithmetic number, because the mean of its divisors is an integer number (930605).

Almost surely, 2^3865581 is an apocalyptic number.

It is an amenable number.

3865581 is a deficient number, since it is larger than the sum of its proper divisors (1718049).

3865581 is a wasteful number, since it uses less digits than its factorization.

3865581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 429515 (or 429512 counting only the distinct ones).

The product of its digits is 28800, while the sum is 36.

The square root of 3865581 is about 1966.1080845162. The cubic root of 3865581 is about 156.9416662944.

The spelling of 3865581 in words is "three million, eight hundred sixty-five thousand, five hundred eighty-one".