3991171 has 4 divisors (see below), whose sum is σ = 3995200. Its totient is φ = 3987144.

The previous prime is 3991139. The next prime is 3991181. The reversal of 3991171 is 1711993.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 3991171 - 2⁵ = 3991139 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 13.

It is not an unprimeable number, because it can be changed into a prime (3991111) 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, 625 + ... + 2893.

It is an arithmetic number, because the mean of its divisors is an integer number (998800).

Almost surely, 2^3991171 is an apocalyptic number.

3991171 is a deficient number, since it is larger than the sum of its proper divisors (4029).

3991171 is a wasteful number, since it uses less digits than its factorization.

3991171 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4028.

The product of its digits is 1701, while the sum is 31.

The square root of 3991171 is about 1997.7915306658. The cubic root of 3991171 is about 158.6232261284.

The spelling of 3991171 in words is "three million, nine hundred ninety-one thousand, one hundred seventy-one".