638378138356 has 24 divisors (see below), whose sum is σ = 1279525838976. Its totient is φ = 272997153120.

The previous prime is 638378138341. The next prime is 638378138357. The reversal of 638378138356 is 653831873836.

It is a junction number, because it is equal to n+sod(n) for n = 638378138294 and 638378138303.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638378138357) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24715096 + ... + 24740911.

It is an arithmetic number, because the mean of its divisors is an integer number (53313576624).

Almost surely, 2^638378138356 is an apocalyptic number.

It is an amenable number.

638378138356 is an abundant number, since it is smaller than the sum of its proper divisors (641147700620).

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

638378138356 is a wasteful number, since it uses less digits than its factorization.

638378138356 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49456479 (or 49456477 counting only the distinct ones).

The product of its digits is 52254720, while the sum is 61.

The spelling of 638378138356 in words is "six hundred thirty-eight billion, three hundred seventy-eight million, one hundred thirty-eight thousand, three hundred fifty-six".