638805204 has 108 divisors (see below), whose sum is σ = 1700406708. Its totient is φ = 209952000.

The previous prime is 638805199. The next prime is 638805221. The reversal of 638805204 is 402508836.

It can be written as a sum of positive squares in 2 ways, for example, as 559417104 + 79388100 = 23652^2 + 8910^2 .

It is a tau number, because it is divible by the number of its divisors (108).

It is a Harshad number since it is a multiple of its sum of digits (36).

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 35 ways as a sum of consecutive naturals, for example, 2650524 + ... + 2650764.

Almost surely, 2^638805204 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638805204, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (850203354).

638805204 is an abundant number, since it is smaller than the sum of its proper divisors (1061601504).

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

638805204 is a wasteful number, since it uses less digits than its factorization.

638805204 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 370 (or 347 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 36.

The square root of 638805204 is about 25274.5960205104. The cubic root of 638805204 is about 861.2372690429.

The spelling of 638805204 in words is "six hundred thirty-eight million, eight hundred five thousand, two hundred four".