638636534744 has 32 divisors (see below), whose sum is σ = 1291066507920. Its totient is φ = 294409731456.

The previous prime is 638636534651. The next prime is 638636534747. The reversal of 638636534744 is 447435636836.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638636534747) 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, 3510782 + ... + 3688205.

Almost surely, 2^638636534744 is an apocalyptic number.

It is an amenable number.

638636534744 is an abundant number, since it is smaller than the sum of its proper divisors (652429973176).

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

638636534744 is a wasteful number, since it uses less digits than its factorization.

638636534744 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7199859 (or 7199855 counting only the distinct ones).

The product of its digits is 104509440, while the sum is 59.

The spelling of 638636534744 in words is "six hundred thirty-eight billion, six hundred thirty-six million, five hundred thirty-four thousand, seven hundred forty-four".