638375013655 has 4 divisors (see below), whose sum is σ = 766050016392. Its totient is φ = 510700010920.

The previous prime is 638375013643. The next prime is 638375013659. The reversal of 638375013655 is 556310573836.

It is a semiprime because it is the product of two primes.

It is a de Polignac number, because none of the positive numbers 2^k-638375013655 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638375013659) 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 3 ways as a sum of consecutive naturals, for example, 63837501361 + ... + 63837501370.

It is an arithmetic number, because the mean of its divisors is an integer number (191512504098).

Almost surely, 2^638375013655 is an apocalyptic number.

638375013655 is a deficient number, since it is larger than the sum of its proper divisors (127675002737).

638375013655 is a wasteful number, since it uses less digits than its factorization.

638375013655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127675002736.

The product of its (nonzero) digits is 6804000, while the sum is 52.

The spelling of 638375013655 in words is "six hundred thirty-eight billion, three hundred seventy-five million, thirteen thousand, six hundred fifty-five".