3909 has 4 divisors (see below), whose sum is σ = 5216. Its totient is φ = 2604.

The previous prime is 3907. The next prime is 3911. The reversal of 3909 is 9093.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (3907) and next prime (3911).

It is not a de Polignac number, because 3909 - 2¹ = 3907 is a prime.

It is a D-number.

It is a Duffinian number.

3909 is a lucky number.

It is a plaindrome in base 5 and base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3907) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 649 + ... + 654.

It is an arithmetic number, because the mean of its divisors is an integer number (1304).

It is an amenable number.

3909 is a deficient number, since it is larger than the sum of its proper divisors (1307).

3909 is a wasteful number, since it uses less digits than its factorization.

3909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1306.

The product of its (nonzero) digits is 243, while the sum is 21.

The square root of 3909 is about 62.5219961294. The cubic root of 3909 is about 15.7527080252.

Subtracting 3909 from its reverse (9093), we obtain a square (5184 = 72²).

The spelling of 3909 in words is "three thousand, nine hundred nine".