638873218 has 8 divisors (see below), whose sum is σ = 958421520. Its totient is φ = 319399380.

The previous prime is 638873201. The next prime is 638873227. The reversal of 638873218 is 812378836.

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

It is a super-3 number, since 3×638873218³ (a number of 27 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14913 + ... + 38731.

It is an arithmetic number, because the mean of its divisors is an integer number (119802690).

Almost surely, 2^638873218 is an apocalyptic number.

638873218 is a deficient number, since it is larger than the sum of its proper divisors (319548302).

638873218 is a wasteful number, since it uses less digits than its factorization.

638873218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37232.

The product of its digits is 387072, while the sum is 46.

The square root of 638873218 is about 25275.9414859269. The cubic root of 638873218 is about 861.2678334531.

The spelling of 638873218 in words is "six hundred thirty-eight million, eight hundred seventy-three thousand, two hundred eighteen".