3686431581 has 40 divisors (see below), whose sum is σ = 6439995584. Its totient is φ = 2057529600.

The previous prime is 3686431577. The next prime is 3686431591. The reversal of 3686431581 is 1851346863.

3686431581 is a `hidden beast` number, since 3 + 6 + 8 + 64 + 3 + 1 + 581 = 666.

It is not a de Polignac number, because 3686431581 - 2² = 3686431577 is a prime.

It is a super-2 number, since 2×3686431581² = 27179555602788319122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3686431501) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 51220 + ... + 99981.

Almost surely, 2^3686431581 is an apocalyptic number.

It is an amenable number.

3686431581 is a deficient number, since it is larger than the sum of its proper divisors (2753564003).

3686431581 is a wasteful number, since it uses less digits than its factorization.

3686431581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151263 (or 151254 counting only the distinct ones).

The product of its digits is 414720, while the sum is 45.

The square root of 3686431581 is about 60715.9911473081. The cubic root of 3686431581 is about 1544.7874266875.

The spelling of 3686431581 in words is "three billion, six hundred eighty-six million, four hundred thirty-one thousand, five hundred eighty-one".