638927099879 has 4 divisors (see below), whose sum is σ = 659537651520. Its totient is φ = 618316548240.

The previous prime is 638927099873. The next prime is 638927099939. The reversal of 638927099879 is 978990729836.

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-638927099879 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 (638927099873) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10305275774 + ... + 10305275835.

It is an arithmetic number, because the mean of its divisors is an integer number (164884412880).

Almost surely, 2^638927099879 is an apocalyptic number.

638927099879 is a deficient number, since it is larger than the sum of its proper divisors (20610551641).

638927099879 is a wasteful number, since it uses less digits than its factorization.

638927099879 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20610551640.

The product of its (nonzero) digits is 740710656, while the sum is 77.

The spelling of 638927099879 in words is "six hundred thirty-eight billion, nine hundred twenty-seven million, ninety-nine thousand, eight hundred seventy-nine".