638842604621 has 8 divisors (see below), whose sum is σ = 702622308864. Its totient is φ = 577154038320.

The previous prime is 638842604611. The next prime is 638842604641. The reversal of 638842604621 is 126406248836.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-638842604621 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 638842604621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638842604611) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 522783845 + ... + 522785066.

It is an arithmetic number, because the mean of its divisors is an integer number (87827788608).

Almost surely, 2^638842604621 is an apocalyptic number.

It is an amenable number.

638842604621 is a deficient number, since it is larger than the sum of its proper divisors (63779704243).

638842604621 is a wasteful number, since it uses less digits than its factorization.

638842604621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1045568971.

The product of its (nonzero) digits is 2654208, while the sum is 50.

The spelling of 638842604621 in words is "six hundred thirty-eight billion, eight hundred forty-two million, six hundred four thousand, six hundred twenty-one".