391678 has 16 divisors (see below), whose sum is σ = 680544. Its totient is φ = 165600.

The previous prime is 391661. The next prime is 391679. The reversal of 391678 is 876193.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391679) by changing a digit.

391678 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1276 + ... + 1552.

It is an arithmetic number, because the mean of its divisors is an integer number (42534).

2³⁹¹⁶⁷⁸ is an apocalyptic number.

391678 is a deficient number, since it is larger than the sum of its proper divisors (288866).

391678 is a wasteful number, since it uses less digits than its factorization.

391678 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 387.

The product of its digits is 9072, while the sum is 34.

The square root of 391678 is about 625.8418330537. The cubic root of 391678 is about 73.1660696560.

The spelling of 391678 in words is "three hundred ninety-one thousand, six hundred seventy-eight".