638403573818 has 8 divisors (see below), whose sum is σ = 957613980960. Its totient is φ = 319198913500.

The previous prime is 638403573803. The next prime is 638403573827. The reversal of 638403573818 is 818375304836.

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1147328 + ... + 1610331.

It is an arithmetic number, because the mean of its divisors is an integer number (119701747620).

Almost surely, 2^638403573818 is an apocalyptic number.

638403573818 is a deficient number, since it is larger than the sum of its proper divisors (319210407142).

638403573818 is a wasteful number, since it uses less digits than its factorization.

638403573818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2873412.

The product of its (nonzero) digits is 11612160, while the sum is 56.

The spelling of 638403573818 in words is "six hundred thirty-eight billion, four hundred three million, five hundred seventy-three thousand, eight hundred eighteen".