638830218 has 16 divisors (see below), whose sum is σ = 1375942176. Its totient is φ = 196563120.

The previous prime is 638830211. The next prime is 638830219. The reversal of 638830218 is 812038836.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is not an unprimeable number, because it can be changed into a prime (638830211) 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 7 ways as a sum of consecutive naturals, for example, 4094988 + ... + 4095143.

It is an arithmetic number, because the mean of its divisors is an integer number (85996386).

Almost surely, 2^638830218 is an apocalyptic number.

638830218 is an abundant number, since it is smaller than the sum of its proper divisors (737111958).

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

638830218 is a wasteful number, since it uses less digits than its factorization.

638830218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8190149.

The product of its (nonzero) digits is 55296, while the sum is 39.

The square root of 638830218 is about 25275.0908603708. The cubic root of 638830218 is about 861.2485101890.

The spelling of 638830218 in words is "six hundred thirty-eight million, eight hundred thirty thousand, two hundred eighteen".