3991646 has 8 divisors (see below), whose sum is σ = 5996280. Its totient is φ = 1992888.

The previous prime is 3991639. The next prime is 3991649. The reversal of 3991646 is 6461993.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3991649) 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, 1205 + ... + 3071.

It is an arithmetic number, because the mean of its divisors is an integer number (749535).

Almost surely, 2^3991646 is an apocalyptic number.

3991646 is a deficient number, since it is larger than the sum of its proper divisors (2004634).

3991646 is a wasteful number, since it uses less digits than its factorization.

3991646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2938.

The product of its digits is 34992, while the sum is 38.

The square root of 3991646 is about 1997.9104084017. The cubic root of 3991646 is about 158.6295186045.

The spelling of 3991646 in words is "three million, nine hundred ninety-one thousand, six hundred forty-six".