391389 has 8 divisors (see below), whose sum is σ = 524832. Its totient is φ = 259440.

The previous prime is 391387. The next prime is 391393. The reversal of 391389 is 983193.

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

It is not a de Polignac number, because 391389 - 2¹ = 391387 is a prime.

391389 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391387) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 619 + ... + 1079.

It is an arithmetic number, because the mean of its divisors is an integer number (65604).

2³⁹¹³⁸⁹ is an apocalyptic number.

It is an amenable number.

391389 is a deficient number, since it is larger than the sum of its proper divisors (133443).

391389 is a wasteful number, since it uses less digits than its factorization.

391389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 747.

The product of its digits is 5832, while the sum is 33.

The square root of 391389 is about 625.6109014395. The cubic root of 391389 is about 73.1480700093.

It can be divided in two parts, 391 and 389, that added together give a triangular number (780 = T₃₉).

The spelling of 391389 in words is "three hundred ninety-one thousand, three hundred eighty-nine".