391688085 has 8 divisors (see below), whose sum is σ = 626700960. Its totient is φ = 208900304.

The previous prime is 391688081. The next prime is 391688107. The reversal of 391688085 is 580886193.

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 391688085 - 2² = 391688081 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391688081) 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 7 ways as a sum of consecutive naturals, for example, 13056255 + ... + 13056284.

It is an arithmetic number, because the mean of its divisors is an integer number (78337620).

Almost surely, 2^391688085 is an apocalyptic number.

It is an amenable number.

391688085 is a deficient number, since it is larger than the sum of its proper divisors (235012875).

391688085 is a wasteful number, since it uses less digits than its factorization.

391688085 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26112547.

The product of its (nonzero) digits is 414720, while the sum is 48.

The square root of 391688085 is about 19791.1112623824. Note that the first 3 decimals coincide. The cubic root of 391688085 is about 731.6669761525. Note that the first 3 decimals are identical.

The spelling of 391688085 in words is "three hundred ninety-one million, six hundred eighty-eight thousand, eighty-five".