3681521 has 4 divisors (see below), whose sum is σ = 3808500. Its totient is φ = 3554544.

The previous prime is 3681511. The next prime is 3681523. The reversal of 3681521 is 1251863.

3681521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1073296 + 2608225 = 1036^2 + 1615^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3681521 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3681523) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 63446 + ... + 63503.

It is an arithmetic number, because the mean of its divisors is an integer number (952125).

Almost surely, 2^3681521 is an apocalyptic number.

It is an amenable number.

3681521 is a deficient number, since it is larger than the sum of its proper divisors (126979).

3681521 is a wasteful number, since it uses less digits than its factorization.

3681521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 126978.

The product of its digits is 1440, while the sum is 26.

The square root of 3681521 is about 1918.7290063998. The cubic root of 3681521 is about 154.4101200782.

The spelling of 3681521 in words is "three million, six hundred eighty-one thousand, five hundred twenty-one".