391089 has 4 divisors (see below), whose sum is σ = 521456. Its totient is φ = 260724.

The previous prime is 391073. The next prime is 391103. The reversal of 391089 is 980193.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 391089 - 2⁴ = 391073 is a prime.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (391009) 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 3 ways as a sum of consecutive naturals, for example, 65179 + ... + 65184.

It is an arithmetic number, because the mean of its divisors is an integer number (130364).

2³⁹¹⁰⁸⁹ is an apocalyptic number.

It is an amenable number.

391089 is a deficient number, since it is larger than the sum of its proper divisors (130367).

391089 is a wasteful number, since it uses less digits than its factorization.

391089 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130366.

The product of its (nonzero) digits is 1944, while the sum is 30.

The square root of 391089 is about 625.3710898339. The cubic root of 391089 is about 73.1293758796.

It can be divided in two parts, 39 and 1089, that added together give a triangular number (1128 = T₄₇).

The spelling of 391089 in words is "three hundred ninety-one thousand, eighty-nine".