638636741064 has 128 divisors (see below), whose sum is σ = 2134124544000. Its totient is φ = 172864072512.

The previous prime is 638636741033. The next prime is 638636741077. The reversal of 638636741064 is 460147636836.

638636741064 is a `hidden beast` number, since 63 + 86 + 36 + 7 + 410 + 64 = 666.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a self number, because there is not a number n which added to its sum of digits gives 638636741064.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 11086504 + ... + 11143959.

It is an arithmetic number, because the mean of its divisors is an integer number (16672848000).

Almost surely, 2^638636741064 is an apocalyptic number.

It is an amenable number.

638636741064 is an abundant number, since it is smaller than the sum of its proper divisors (1495487802936).

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

638636741064 is a wasteful number, since it uses less digits than its factorization.

638636741064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22230504 (or 22230494 counting only the distinct ones).

The product of its (nonzero) digits is 10450944, while the sum is 54.

The spelling of 638636741064 in words is "six hundred thirty-eight billion, six hundred thirty-six million, seven hundred forty-one thousand, sixty-four".