391597 has 4 divisors (see below), whose sum is σ = 393820. Its totient is φ = 389376.

The previous prime is 391579. The next prime is 391613. The reversal of 391597 is 795193.

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

It can be written as a sum of positive squares in 2 ways, for example, as 276676 + 114921 = 526^2 + 339^2 .

It is a cyclic number.

It is not a de Polignac number, because 391597 - 2¹⁵ = 358829 is a prime.

It is an Ulam number.

It is a Duffinian number.

391597 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391537) 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, 822 + ... + 1207.

It is an arithmetic number, because the mean of its divisors is an integer number (98455).

2³⁹¹⁵⁹⁷ is an apocalyptic number.

It is an amenable number.

391597 is a deficient number, since it is larger than the sum of its proper divisors (2223).

391597 is a wasteful number, since it uses less digits than its factorization.

391597 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2222.

The product of its digits is 8505, while the sum is 34.

The square root of 391597 is about 625.7771168715. Note that the first 3 decimals coincide. The cubic root of 391597 is about 73.1610256656.

The spelling of 391597 in words is "three hundred ninety-one thousand, five hundred ninety-seven".