391385997 has 12 divisors (see below), whose sum is σ = 595090080. Its totient is φ = 247191048.

The previous prime is 391385989. The next prime is 391386013. The reversal of 391385997 is 799583193.

391385997 is a `hidden beast` number, since 39 + 13 + 8 + 599 + 7 = 666.

It is not a de Polignac number, because 391385997 - 2³ = 391385989 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391385947) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1144233 + ... + 1144574.

It is an arithmetic number, because the mean of its divisors is an integer number (49590840).

Almost surely, 2^391385997 is an apocalyptic number.

It is an amenable number.

391385997 is a deficient number, since it is larger than the sum of its proper divisors (203704083).

391385997 is a wasteful number, since it uses less digits than its factorization.

391385997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2288832 (or 2288829 counting only the distinct ones).

The product of its digits is 1837080, while the sum is 54.

The square root of 391385997 is about 19783.4778792810. The cubic root of 391385997 is about 731.4788292838.

The spelling of 391385997 in words is "three hundred ninety-one million, three hundred eighty-five thousand, nine hundred ninety-seven".