3681809 has 4 divisors (see below), whose sum is σ = 3898404. Its totient is φ = 3465216.

The previous prime is 3681793. The next prime is 3681823. The reversal of 3681809 is 9081863.

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 1918225 + 1763584 = 1385^2 + 1328^2 .

It is a cyclic number.

It is not a de Polignac number, because 3681809 - 2⁴ = 3681793 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (3681889) 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, 108272 + ... + 108305.

It is an arithmetic number, because the mean of its divisors is an integer number (974601).

Almost surely, 2^3681809 is an apocalyptic number.

It is an amenable number.

3681809 is a deficient number, since it is larger than the sum of its proper divisors (216595).

3681809 is a wasteful number, since it uses less digits than its factorization.

3681809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 216594.

The product of its (nonzero) digits is 10368, while the sum is 35.

The square root of 3681809 is about 1918.8040546132. The cubic root of 3681809 is about 154.4141463991.

The spelling of 3681809 in words is "three million, six hundred eighty-one thousand, eight hundred nine".