391688168 has 8 divisors (see below), whose sum is σ = 734415330. Its totient is φ = 195844080.

The previous prime is 391688147. The next prime is 391688203. The reversal of 391688168 is 861886193.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 384081604 + 7606564 = 19598^2 + 2758^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 24480503 + ... + 24480518.

Almost surely, 2^391688168 is an apocalyptic number.

It is an amenable number.

391688168 is a deficient number, since it is larger than the sum of its proper divisors (342727162).

391688168 is a wasteful number, since it uses less digits than its factorization.

391688168 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48961027 (or 48961023 counting only the distinct ones).

The product of its digits is 497664, while the sum is 50.

The square root of 391688168 is about 19791.1133592833. The cubic root of 391688168 is about 731.6670278334.

The spelling of 391688168 in words is "three hundred ninety-one million, six hundred eighty-eight thousand, one hundred sixty-eight".