638699996837 has 12 divisors (see below), whose sum is σ = 743065430796. Its totient is φ = 547392384000.

The previous prime is 638699996827. The next prime is 638699996881. The reversal of 638699996837 is 738699996836.

638699996837 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 16314697441 + 622385299396 = 127729^2 + 788914^2 .

It is not a de Polignac number, because 638699996837 - 2²⁸ = 638431561381 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 (638699996827) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 350108 + ... + 1183205.

It is an arithmetic number, because the mean of its divisors is an integer number (61922119233).

Almost surely, 2^638699996837 is an apocalyptic number.

It is an amenable number.

638699996837 is a deficient number, since it is larger than the sum of its proper divisors (104365433959).

638699996837 is a wasteful number, since it uses less digits than its factorization.

638699996837 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1541828 (or 1541821 counting only the distinct ones).

The product of its digits is 5714053632, while the sum is 83.

Subtracting 638699996837 from its reverse (738699996836), we obtain a palindrome (99999999999).

The spelling of 638699996837 in words is "six hundred thirty-eight billion, six hundred ninety-nine million, nine hundred ninety-six thousand, eight hundred thirty-seven".