3681 has 6 divisors (see below), whose sum is σ = 5330. Its totient is φ = 2448.

The previous prime is 3677. The next prime is 3691. The reversal of 3681 is 1863.

3681 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 3600 + 81 = 60^2 + 9^2 .

It is not a de Polignac number, because 3681 - 2² = 3677 is a prime.

It is a super-2 number, since 2×3681² = 27099522, which contains 22 as substring.

It is a Duffinian number.

3681 is a modest number, since divided by 81 gives 36 as remainder.

It is a plaindrome in base 14 and base 15.

It is a nialpdrome in base 16.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 3681.

It is not an unprimeable number, because it can be changed into a prime (3631) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 196 + ... + 213.

2³⁶⁸¹ is an apocalyptic number.

It is an amenable number.

3681 is a deficient number, since it is larger than the sum of its proper divisors (1649).

3681 is a wasteful number, since it uses less digits than its factorization.

3681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 415 (or 412 counting only the distinct ones).

The product of its digits is 144, while the sum is 18.

The square root of 3681 is about 60.6712452485. The cubic root of 3681 is about 15.4402835818.

Subtracting from 3681 its sum of digits (18), we obtain a palindrome (3663).

It can be divided in two parts, 36 and 81, that multiplied together give a square (2916 = 54²).

The spelling of 3681 in words is "three thousand, six hundred eighty-one".