3991617 has 24 divisors (see below), whose sum is σ = 6978816. Its totient is φ = 2146176.

The previous prime is 3991613. The next prime is 3991619. The reversal of 3991617 is 7161993.

3991617 is a `hidden beast` number, since 39 + 9 + 1 + 617 = 666.

It is not a de Polignac number, because 3991617 - 2² = 3991613 is a prime.

It is not an unprimeable number, because it can be changed into a prime (3991613) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 793 + ... + 2934.

It is an arithmetic number, because the mean of its divisors is an integer number (290784).

Almost surely, 2^3991617 is an apocalyptic number.

It is an amenable number.

3991617 is a deficient number, since it is larger than the sum of its proper divisors (2987199).

3991617 is a wasteful number, since it uses less digits than its factorization.

3991617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3757 (or 3754 counting only the distinct ones).

The product of its digits is 10206, while the sum is 36.

The square root of 3991617 is about 1997.9031508059. The cubic root of 3991617 is about 158.6291344465.

It can be divided in two parts, 399 and 1617, that added together give a triangular number (2016 = T₆₃).

The spelling of 3991617 in words is "three million, nine hundred ninety-one thousand, six hundred seventeen".