3991165 has 8 divisors (see below), whose sum is σ = 4880088. Its totient is φ = 3132480.

The previous prime is 3991139. The next prime is 3991181. The reversal of 3991165 is 5611993.

It can be written as a sum of positive squares in 4 ways, for example, as 1205604 + 2785561 = 1098^2 + 1669^2 .

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

It is not a de Polignac number, because 3991165 - 2⁷ = 3991037 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 3991165.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7266 + ... + 7795.

It is an arithmetic number, because the mean of its divisors is an integer number (610011).

Almost surely, 2^3991165 is an apocalyptic number.

It is an amenable number.

3991165 is a deficient number, since it is larger than the sum of its proper divisors (888923).

3991165 is a wasteful number, since it uses less digits than its factorization.

3991165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15119.

The product of its digits is 7290, while the sum is 34.

The square root of 3991165 is about 1997.7900290071. The cubic root of 3991165 is about 158.6231466413.

It can be divided in two parts, 39 and 91165, that added together give a square (91204 = 302²).

The spelling of 3991165 in words is "three million, nine hundred ninety-one thousand, one hundred sixty-five".