391647 has 8 divisors (see below), whose sum is σ = 549760. Its totient is φ = 247320.

The previous prime is 391639. The next prime is 391661. The reversal of 391647 is 746193.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 391647 - 2³ = 391639 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391627) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3379 + ... + 3492.

It is an arithmetic number, because the mean of its divisors is an integer number (68720).

2³⁹¹⁶⁴⁷ is an apocalyptic number.

391647 is a deficient number, since it is larger than the sum of its proper divisors (158113).

391647 is a wasteful number, since it uses less digits than its factorization.

391647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6893.

The product of its digits is 4536, while the sum is 30.

The square root of 391647 is about 625.8170659226. The cubic root of 391647 is about 73.1641393221.

The spelling of 391647 in words is "three hundred ninety-one thousand, six hundred forty-seven".