391684 has 12 divisors (see below), whose sum is σ = 690508. Its totient is φ = 194400.

The previous prime is 391679. The next prime is 391691. The reversal of 391684 is 486193.

It can be written as a sum of positive squares in 2 ways, for example, as 57600 + 334084 = 240^2 + 578^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 454 + ... + 994.

2³⁹¹⁶⁸⁴ is an apocalyptic number.

It is an amenable number.

391684 is a deficient number, since it is larger than the sum of its proper divisors (298824).

391684 is a wasteful number, since it uses less digits than its factorization.

391684 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 726 (or 724 counting only the distinct ones).

The product of its digits is 5184, while the sum is 31.

The square root of 391684 is about 625.8466265787. The cubic root of 391684 is about 73.1664432572.

The spelling of 391684 in words is "three hundred ninety-one thousand, six hundred eighty-four".