391617 has 12 divisors (see below), whose sum is σ = 577044. Its totient is φ = 255840.

The previous prime is 391613. The next prime is 391619. The reversal of 391617 is 716193.

It can be written as a sum of positive squares in 2 ways, for example, as 194481 + 197136 = 441^2 + 444^2 .

It is not a de Polignac number, because 391617 - 2² = 391613 is a prime.

It is an Ulam number.

391617 is a lucky number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 391617.

It is not an unprimeable number, because it can be changed into a prime (391613) 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 11 ways as a sum of consecutive naturals, for example, 67 + ... + 887.

It is an arithmetic number, because the mean of its divisors is an integer number (48087).

2³⁹¹⁶¹⁷ is an apocalyptic number.

It is an amenable number.

391617 is a deficient number, since it is larger than the sum of its proper divisors (185427).

391617 is a wasteful number, since it uses less digits than its factorization.

391617 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 880 (or 877 counting only the distinct ones).

The product of its digits is 1134, while the sum is 27.

The square root of 391617 is about 625.7930967980. The cubic root of 391617 is about 73.1622711600.

The spelling of 391617 in words is "three hundred ninety-one thousand, six hundred seventeen".