3991105 has 4 divisors (see below), whose sum is σ = 4789332. Its totient is φ = 3192880.

The previous prime is 3991103. The next prime is 3991111. The reversal of 3991105 is 5011993.

3991105 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5011993 = 7 ⋅715999.

It can be written as a sum of positive squares in 2 ways, for example, as 2745649 + 1245456 = 1657^2 + 1116^2 .

It is not a de Polignac number, because 3991105 - 2¹ = 3991103 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3991103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 399106 + ... + 399115.

It is an arithmetic number, because the mean of its divisors is an integer number (1197333).

Almost surely, 2^3991105 is an apocalyptic number.

It is an amenable number.

3991105 is a deficient number, since it is larger than the sum of its proper divisors (798227).

3991105 is an equidigital number, since it uses as much as digits as its factorization.

3991105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 798226.

The product of its (nonzero) digits is 1215, while the sum is 28.

The square root of 3991105 is about 1997.7750123575. The cubic root of 3991105 is about 158.6223517659.

It can be divided in two parts, 3991 and 105, that added together give a 12-th power (4096 = 2¹²).

The spelling of 3991105 in words is "three million, nine hundred ninety-one thousand, one hundred five".