391382857 has 8 divisors (see below), whose sum is σ = 420083496. Its totient is φ = 363313152.

The previous prime is 391382851. The next prime is 391382863. The reversal of 391382857 is 758283193.

It is an interprime number because it is at equal distance from previous prime (391382851) and next prime (391382863).

It can be written as a sum of positive squares in 4 ways, for example, as 211527936 + 179854921 = 14544^2 + 13411^2 .

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 391382857 - 2¹¹ = 391380809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (391382851) 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, 156448 + ... + 158929.

It is an arithmetic number, because the mean of its divisors is an integer number (52510437).

Almost surely, 2^391382857 is an apocalyptic number.

It is an amenable number.

391382857 is a deficient number, since it is larger than the sum of its proper divisors (28700639).

391382857 is a wasteful number, since it uses less digits than its factorization.

391382857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 315467.

The product of its digits is 362880, while the sum is 46.

The square root of 391382857 is about 19783.3985199712. The cubic root of 391382857 is about 731.4768731163.

The spelling of 391382857 in words is "three hundred ninety-one million, three hundred eighty-two thousand, eight hundred fifty-seven".