391099 has 4 divisors (see below), whose sum is σ = 400680. Its totient is φ = 381520.

The previous prime is 391073. The next prime is 391103. The reversal of 391099 is 990193.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 990193 = 67 ⋅14779.

It is a cyclic number.

It is not a de Polignac number, because 391099 - 2⁵ = 391067 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an Ulam number.

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 391099.

It is not an unprimeable number, because it can be changed into a prime (391009) 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, 4729 + ... + 4810.

It is an arithmetic number, because the mean of its divisors is an integer number (100170).

2³⁹¹⁰⁹⁹ is an apocalyptic number.

391099 is a deficient number, since it is larger than the sum of its proper divisors (9581).

391099 is an equidigital number, since it uses as much as digits as its factorization.

391099 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9580.

The product of its (nonzero) digits is 2187, while the sum is 31.

The square root of 391099 is about 625.3790850356. The cubic root of 391099 is about 73.1299991712.

The spelling of 391099 in words is "three hundred ninety-one thousand, ninety-nine".