391439609 has 16 divisors (see below), whose sum is σ = 436155840. Its totient is φ = 348279360.

The previous prime is 391439597. The next prime is 391439611. The reversal of 391439609 is 906934193.

It is not a de Polignac number, because 391439609 - 2⁸ = 391439353 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 391439609.

It is not an unprimeable number, because it can be changed into a prime (391439639) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 412874 + ... + 413820.

It is an arithmetic number, because the mean of its divisors is an integer number (27259740).

Almost surely, 2^391439609 is an apocalyptic number.

It is an amenable number.

391439609 is a deficient number, since it is larger than the sum of its proper divisors (44716231).

391439609 is a wasteful number, since it uses less digits than its factorization.

391439609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1720.

The product of its (nonzero) digits is 157464, while the sum is 44.

The square root of 391439609 is about 19784.8328019218. The cubic root of 391439609 is about 731.5122270486.

The spelling of 391439609 in words is "three hundred ninety-one million, four hundred thirty-nine thousand, six hundred nine".