3991271 has 4 divisors (see below), whose sum is σ = 4066632. Its totient is φ = 3915912.

The previous prime is 3991261. The next prime is 3991279. The reversal of 3991271 is 1721993.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3991271 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3991279) 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, 37601 + ... + 37706.

It is an arithmetic number, because the mean of its divisors is an integer number (1016658).

Almost surely, 2^3991271 is an apocalyptic number.

3991271 is a deficient number, since it is larger than the sum of its proper divisors (75361).

3991271 is an equidigital number, since it uses as much as digits as its factorization.

3991271 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75360.

The product of its digits is 3402, while the sum is 32.

The square root of 3991271 is about 1997.8165581454. The cubic root of 3991271 is about 158.6245509017.

The spelling of 3991271 in words is "three million, nine hundred ninety-one thousand, two hundred seventy-one".