638940708 has 36 divisors (see below), whose sum is σ = 1845829440. Its totient is φ = 182554416.

The previous prime is 638940697. The next prime is 638940719. The reversal of 638940708 is 807049836.

It is a happy number.

638940708 is a `hidden beast` number, since 638 + 9 + 4 + 0 + 7 + 0 + 8 = 666.

It is an interprime number because it is at equal distance from previous prime (638940697) and next prime (638940719).

It is a tau number, because it is divible by the number of its divisors (36).

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 11 ways as a sum of consecutive naturals, for example, 1267488 + ... + 1267991.

It is an arithmetic number, because the mean of its divisors is an integer number (51273040).

Almost surely, 2^638940708 is an apocalyptic number.

It is an amenable number.

638940708 is an abundant number, since it is smaller than the sum of its proper divisors (1206888732).

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

638940708 is a wasteful number, since it uses less digits than its factorization.

638940708 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2535496 (or 2535491 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 45.

The square root of 638940708 is about 25277.2765146880. The cubic root of 638940708 is about 861.2981602419.

The spelling of 638940708 in words is "six hundred thirty-eight million, nine hundred forty thousand, seven hundred eight".