638796918 has 8 divisors (see below), whose sum is σ = 1277593848. Its totient is φ = 212932304.

The previous prime is 638796911. The next prime is 638796931. The reversal of 638796918 is 819697836.

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

638796918 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638796911) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 53233071 + ... + 53233082.

It is an arithmetic number, because the mean of its divisors is an integer number (159699231).

Almost surely, 2^638796918 is an apocalyptic number.

638796918 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

638796918 is a wasteful number, since it uses less digits than its factorization.

638796918 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106466158.

The product of its digits is 3919104, while the sum is 57.

The square root of 638796918 is about 25274.4321004449. The cubic root of 638796918 is about 861.2335452980.

The spelling of 638796918 in words is "six hundred thirty-eight million, seven hundred ninety-six thousand, nine hundred eighteen".