638842618031 has 4 divisors (see below), whose sum is σ = 638946619392. Its totient is φ = 638738616672.

The previous prime is 638842618019. The next prime is 638842618033. The reversal of 638842618031 is 130816248836.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-638842618031 is a prime.

It is a super-2 number, since 2×638842618031² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638842618033) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 51991466 + ... + 52003751.

It is an arithmetic number, because the mean of its divisors is an integer number (159736654848).

Almost surely, 2^638842618031 is an apocalyptic number.

638842618031 is a deficient number, since it is larger than the sum of its proper divisors (104001361).

638842618031 is a wasteful number, since it uses less digits than its factorization.

638842618031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104001360.

The product of its (nonzero) digits is 1327104, while the sum is 50.

The spelling of 638842618031 in words is "six hundred thirty-eight billion, eight hundred forty-two million, six hundred eighteen thousand, thirty-one".