3981691 has 12 divisors (see below), whose sum is σ = 4834512. Its totient is φ = 3263568.

The previous prime is 3981683. The next prime is 3981707. The reversal of 3981691 is 1961893.

It is not a de Polignac number, because 3981691 - 2³ = 3981683 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 3981691.

It is not an unprimeable number, because it can be changed into a prime (3981641) 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 11 ways as a sum of consecutive naturals, for example, 640 + ... + 2893.

It is an arithmetic number, because the mean of its divisors is an integer number (402876).

Almost surely, 2^3981691 is an apocalyptic number.

3981691 is a deficient number, since it is larger than the sum of its proper divisors (852821).

3981691 is a wasteful number, since it uses less digits than its factorization.

3981691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3570 (or 3563 counting only the distinct ones).

The product of its digits is 11664, while the sum is 37.

The square root of 3981691 is about 1995.4175001738. The cubic root of 3981691 is about 158.4975370056.

The spelling of 3981691 in words is "three million, nine hundred eighty-one thousand, six hundred ninety-one".