638399909043468 has 384 divisors, whose sum is σ = 1954068962227200. Its totient is φ = 177691826995200.

The previous prime is 638399909043443. The next prime is 638399909043497. The reversal of 638399909043468 is 864340909993836.

638399909043468 is a `hidden beast` number, since 6 + 3 + 8 + 3 + 9 + 9 + 90 + 90 + 434 + 6 + 8 = 666.

638399909043468 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 19398929398 + ... + 19398962306.

It is an arithmetic number, because the mean of its divisors is an integer number (5088721255800).

Almost surely, 2^{638399909043468} 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 638399909043468, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (977034481113600).

638399909043468 is an abundant number, since it is smaller than the sum of its proper divisors (1315669053183732).

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

638399909043468 is a wasteful number, since it uses less digits than its factorization.

638399909043468 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39110 (or 39102 counting only the distinct ones).

The product of its (nonzero) digits is 6530347008, while the sum is 81.

The spelling of 638399909043468 in words is "six hundred thirty-eight trillion, three hundred ninety-nine billion, nine hundred nine million, forty-three thousand, four hundred sixty-eight".