3991811 has 8 divisors (see below), whose sum is σ = 4191264. Its totient is φ = 3794560.

The previous prime is 3991807. The next prime is 3991817. The reversal of 3991811 is 1181993.

3991811 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 3991811 - 2² = 3991807 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3991817) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4091 + ... + 4971.

It is an arithmetic number, because the mean of its divisors is an integer number (523908).

Almost surely, 2^3991811 is an apocalyptic number.

3991811 is a deficient number, since it is larger than the sum of its proper divisors (199453).

3991811 is a wasteful number, since it uses less digits than its factorization.

3991811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1101.

The product of its digits is 1944, while the sum is 32.

The square root of 3991811 is about 1997.9517011179. The cubic root of 3991811 is about 158.6317042951.

The spelling of 3991811 in words is "three million, nine hundred ninety-one thousand, eight hundred eleven".