3811581 has 6 divisors (see below), whose sum is σ = 5505630. Its totient is φ = 2541048.

The previous prime is 3811579. The next prime is 3811589. The reversal of 3811581 is 1851183.

3811581 is a `hidden beast` number, since 3 + 81 + 1 + 581 = 666.

It can be written as a sum of positive squares in only one way, i.e., 3767481 + 44100 = 1941^2 + 210^2 .

It is not a de Polignac number, because 3811581 - 2¹ = 3811579 is a prime.

It is a super-2 number, since 2×3811581² = 29056299439122, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3811589) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 211746 + ... + 211763.

It is an arithmetic number, because the mean of its divisors is an integer number (917605).

Almost surely, 2^3811581 is an apocalyptic number.

It is an amenable number.

3811581 is a deficient number, since it is larger than the sum of its proper divisors (1694049).

3811581 is a wasteful number, since it uses less digits than its factorization.

3811581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 423515 (or 423512 counting only the distinct ones).

The product of its digits is 960, while the sum is 27.

The square root of 3811581 is about 1952.3270730080. The cubic root of 3811581 is about 156.2074409956.

The spelling of 3811581 in words is "three million, eight hundred eleven thousand, five hundred eighty-one".