3686521 has 4 divisors (see below), whose sum is σ = 3756132. Its totient is φ = 3616912.

The previous prime is 3686503. The next prime is 3686531. The reversal of 3686521 is 1256863.

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 2676496 + 1010025 = 1636^2 + 1005^2 .

It is a cyclic number.

It is not a de Polignac number, because 3686521 - 2⁹ = 3686009 is a prime.

It is a d-powerful number, because it can be written as 3¹³ + 6³ + 8 + 6⁵ + 5⁹ + 2¹⁷ + 1 .

It is a Duffinian number.

3686521 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (3686531) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34726 + ... + 34831.

It is an arithmetic number, because the mean of its divisors is an integer number (939033).

Almost surely, 2^3686521 is an apocalyptic number.

It is an amenable number.

3686521 is a deficient number, since it is larger than the sum of its proper divisors (69611).

3686521 is an equidigital number, since it uses as much as digits as its factorization.

3686521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69610.

The product of its digits is 8640, while the sum is 31.

The square root of 3686521 is about 1920.0315101581. The cubic root of 3686521 is about 154.4799916836.

It can be divided in two parts, 368 and 6521, that added together give a square (6889 = 83²).

The spelling of 3686521 in words is "three million, six hundred eighty-six thousand, five hundred twenty-one".