3881809 has 4 divisors (see below), whose sum is σ = 3902116. Its totient is φ = 3861504.

The previous prime is 3881807. The next prime is 3881837. The reversal of 3881809 is 9081883.

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 540225 + 3341584 = 735^2 + 1828^2 .

It is a cyclic number.

It is not a de Polignac number, because 3881809 - 2¹ = 3881807 is a prime.

It is a super-2 number, since 2×3881809² = 30136882224962, which contains 22 as substring.

It is a Duffinian number.

3881809 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (3881803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9864 + ... + 10249.

It is an arithmetic number, because the mean of its divisors is an integer number (975529).

Almost surely, 2^3881809 is an apocalyptic number.

It is an amenable number.

3881809 is a deficient number, since it is larger than the sum of its proper divisors (20307).

3881809 is a wasteful number, since it uses less digits than its factorization.

3881809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20306.

The product of its (nonzero) digits is 13824, while the sum is 37.

The square root of 3881809 is about 1970.2306971520. The cubic root of 3881809 is about 157.1609773280.

It can be divided in two parts, 388 and 1809, that added together give a cube (2197 = 13³).

The spelling of 3881809 in words is "three million, eight hundred eighty-one thousand, eight hundred nine".