391998858 has 16 divisors (see below), whose sum is σ = 811032480. Its totient is φ = 126160496.

The previous prime is 391998857. The next prime is 391998883. The reversal of 391998858 is 858899193.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (391998851) 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, 1126260 + ... + 1126607.

It is an arithmetic number, because the mean of its divisors is an integer number (50689530).

Almost surely, 2^391998858 is an apocalyptic number.

391998858 is an abundant number, since it is smaller than the sum of its proper divisors (419033622).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

391998858 is a wasteful number, since it uses less digits than its factorization.

391998858 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2252901.

The product of its digits is 5598720, while the sum is 60.

The square root of 391998858 is about 19798.9610333472. The cubic root of 391998858 is about 731.8604313020.

The spelling of 391998858 in words is "three hundred ninety-one million, nine hundred ninety-eight thousand, eight hundred fifty-eight".