638818005 has 32 divisors (see below), whose sum is σ = 1170597888. Its totient is φ = 291412800.

The previous prime is 638817967. The next prime is 638818009. The reversal of 638818005 is 500818836.

It is a happy number.

638818005 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 638818005 - 2²² = 634623701 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638818009) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 45360 + ... + 57750.

It is an arithmetic number, because the mean of its divisors is an integer number (36581184).

Almost surely, 2^638818005 is an apocalyptic number.

It is an amenable number.

638818005 is a deficient number, since it is larger than the sum of its proper divisors (531779883).

638818005 is a wasteful number, since it uses less digits than its factorization.

638818005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12897.

The product of its (nonzero) digits is 46080, while the sum is 39.

The square root of 638818005 is about 25274.8492577107. The cubic root of 638818005 is about 861.2430217745.

The spelling of 638818005 in words is "six hundred thirty-eight million, eight hundred eighteen thousand, five".