391109 has 4 divisors (see below), whose sum is σ = 392460. Its totient is φ = 389760.

The previous prime is 391103. The next prime is 391117. The reversal of 391109 is 901193.

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 can be written as a sum of positive squares in 2 ways, for example, as 4225 + 386884 = 65^2 + 622^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-391109 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 44 + ... + 885.

It is an arithmetic number, because the mean of its divisors is an integer number (98115).

2³⁹¹¹⁰⁹ is an apocalyptic number.

It is an amenable number.

391109 is a deficient number, since it is larger than the sum of its proper divisors (1351).

391109 is an equidigital number, since it uses as much as digits as its factorization.

391109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1350.

The product of its (nonzero) digits is 243, while the sum is 23.

The square root of 391109 is about 625.3870801352. The cubic root of 391109 is about 73.1306224522.

The spelling of 391109 in words is "three hundred ninety-one thousand, one hundred nine".