391668539 has 8 divisors (see below), whose sum is σ = 406225920. Its totient is φ = 377231400.

The previous prime is 391668499. The next prime is 391668551. The reversal of 391668539 is 935866193.

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

It is a cyclic number.

It is not a de Polignac number, because 391668539 - 2²⁰ = 390619963 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (391668239) 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, 23399 + ... + 36480.

It is an arithmetic number, because the mean of its divisors is an integer number (50778240).

Almost surely, 2^391668539 is an apocalyptic number.

391668539 is a deficient number, since it is larger than the sum of its proper divisors (14557381).

391668539 is a wasteful number, since it uses less digits than its factorization.

391668539 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60121.

The product of its digits is 1049760, while the sum is 50.

The square root of 391668539 is about 19790.6174486801. The cubic root of 391668539 is about 731.6548054133.

The spelling of 391668539 in words is "three hundred ninety-one million, six hundred sixty-eight thousand, five hundred thirty-nine".