638861731807 has 16 divisors (see below), whose sum is σ = 728519400000. Its totient is φ = 554995994112.

The previous prime is 638861731763. The next prime is 638861731847. The reversal of 638861731807 is 708137168836.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-638861731807 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 (638861731847) 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 15 ways as a sum of consecutive naturals, for example, 4066438 + ... + 4220620.

It is an arithmetic number, because the mean of its divisors is an integer number (45532462500).

Almost surely, 2^638861731807 is an apocalyptic number.

638861731807 is a deficient number, since it is larger than the sum of its proper divisors (89657668193).

638861731807 is a wasteful number, since it uses less digits than its factorization.

638861731807 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172962.

The product of its (nonzero) digits is 8128512, while the sum is 58.

The spelling of 638861731807 in words is "six hundred thirty-eight billion, eight hundred sixty-one million, seven hundred thirty-one thousand, eight hundred seven".