646816518 has 24 divisors (see below), whose sum is σ = 1401937056. Its totient is φ = 215528400.

The previous prime is 646816507. The next prime is 646816523. The reversal of 646816518 is 815618646.

646816518 is a `hidden beast` number, since 64 + 68 + 16 + 518 = 666.

It is a congruent number.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 69628 + ... + 78368.

It is an arithmetic number, because the mean of its divisors is an integer number (58414044).

Almost surely, 2^646816518 is an apocalyptic number.

646816518 is an abundant number, since it is smaller than the sum of its proper divisors (755120538).

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

646816518 is a wasteful number, since it uses less digits than its factorization.

646816518 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12860 (or 12857 counting only the distinct ones).

The product of its digits is 276480, while the sum is 45.

The square root of 646816518 is about 25432.5877173362. The cubic root of 646816518 is about 864.8226074357.

The spelling of 646816518 in words is "six hundred forty-six million, eight hundred sixteen thousand, five hundred eighteen".