638706007440 has 240 divisors, whose sum is σ = 2241575601408. Its totient is φ = 162820675584.

The previous prime is 638706007439. The next prime is 638706007493. The reversal of 638706007440 is 44700607836.

638706007440 is a `hidden beast` number, since 6 + 38 + 7 + 0 + 600 + 7 + 4 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (45).

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 47 ways as a sum of consecutive naturals, for example, 1235652 + ... + 1674588.

Almost surely, 2^638706007440 is an apocalyptic number.

638706007440 is a gapful number since it is divisible by the number (60) 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 638706007440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1120787800704).

638706007440 is an abundant number, since it is smaller than the sum of its proper divisors (1602869593968).

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

638706007440 is a wasteful number, since it uses less digits than its factorization.

638706007440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 439046 (or 439037 counting only the distinct ones).

The product of its (nonzero) digits is 677376, while the sum is 45.

The spelling of 638706007440 in words is "six hundred thirty-eight billion, seven hundred six million, seven thousand, four hundred forty".