3990409 has 4 divisors (see below), whose sum is σ = 4030020. Its totient is φ = 3950800.

The previous prime is 3990383. The next prime is 3990419. The reversal of 3990409 is 9040993.

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 2550409 + 1440000 = 1597^2 + 1200^2 .

It is a cyclic number.

It is not a de Polignac number, because 3990409 - 2⁷ = 3990281 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3990419) 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, 19654 + ... + 19855.

It is an arithmetic number, because the mean of its divisors is an integer number (1007505).

Almost surely, 2^3990409 is an apocalyptic number.

It is an amenable number.

3990409 is a deficient number, since it is larger than the sum of its proper divisors (39611).

3990409 is a wasteful number, since it uses less digits than its factorization.

3990409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39610.

The product of its (nonzero) digits is 8748, while the sum is 34.

The square root of 3990409 is about 1997.6008109730. The cubic root of 3990409 is about 158.6131306292.

The spelling of 3990409 in words is "three million, nine hundred ninety thousand, four hundred nine".