638736344064 has 704 divisors, whose sum is σ = 2347663360000. Its totient is φ = 167047888896.

The previous prime is 638736344047. The next prime is 638736344089. The reversal of 638736344064 is 460443637836.

638736344064 is a `hidden beast` number, since 6 + 3 + 87 + 3 + 63 + 440 + 64 = 666.

It is a hoax number, since the sum of its digits (54) coincides with the sum of the digits of its distinct 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 638736344064.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 319526937 + ... + 319528935.

Almost surely, 2^638736344064 is an apocalyptic number.

638736344064 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638736344064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1173831680000).

638736344064 is an abundant number, since it is smaller than the sum of its proper divisors (1708927015936).

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

638736344064 is a wasteful number, since it uses less digits than its factorization.

638736344064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2175 (or 2151 counting only the distinct ones).

The product of its (nonzero) digits is 20901888, while the sum is 54.

The spelling of 638736344064 in words is "six hundred thirty-eight billion, seven hundred thirty-six million, three hundred forty-four thousand, sixty-four".