391984 has 10 divisors (see below), whose sum is σ = 759500. Its totient is φ = 195984.

The previous prime is 391967. The next prime is 391987. The reversal of 391984 is 489193.

It is not an unprimeable number, because it can be changed into a prime (391987) by changing a digit.

391984 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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 as a sum of consecutive naturals, namely, 12234 + ... + 12265.

It is an arithmetic number, because the mean of its divisors is an integer number (75950).

2³⁹¹⁹⁸⁴ is an apocalyptic number.

It is an amenable number.

391984 is a deficient number, since it is larger than the sum of its proper divisors (367516).

391984 is a wasteful number, since it uses less digits than its factorization.

391984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24507 (or 24501 counting only the distinct ones).

The product of its digits is 7776, while the sum is 34.

The square root of 391984 is about 626.0862560383. The cubic root of 391984 is about 73.1851184575.

The spelling of 391984 in words is "three hundred ninety-one thousand, nine hundred eighty-four".