638484138 has 24 divisors (see below), whose sum is σ = 1404032448. Its totient is φ = 209651112.

The previous prime is 638484107. The next prime is 638484139. The reversal of 638484138 is 831484836.

638484138 is a `hidden beast` number, since 6 + 38 + 484 + 138 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 638484093 and 638484102.

It is not an unprimeable number, because it can be changed into a prime (638484139) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 263506 + ... + 265917.

It is an arithmetic number, because the mean of its divisors is an integer number (58501352).

Almost surely, 2^638484138 is an apocalyptic number.

638484138 is an abundant number, since it is smaller than the sum of its proper divisors (765548310).

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

638484138 is a wasteful number, since it uses less digits than its factorization.

638484138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 529498 (or 529495 counting only the distinct ones).

The product of its digits is 442368, while the sum is 45.

The square root of 638484138 is about 25268.2436667054. The cubic root of 638484138 is about 861.0929577871.

The spelling of 638484138 in words is "six hundred thirty-eight million, four hundred eighty-four thousand, one hundred thirty-eight".