638607805879 has 2 divisors, whose sum is σ = 638607805880. Its totient is φ = 638607805878.

The previous prime is 638607805877. The next prime is 638607805883. The reversal of 638607805879 is 978508706836.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 638607805879 - 2¹ = 638607805877 is a prime.

Together with 638607805877, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638607805877) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319303902939 + 319303902940.

It is an arithmetic number, because the mean of its divisors is an integer number (319303902940).

Almost surely, 2^638607805879 is an apocalyptic number.

638607805879 is a deficient number, since it is larger than the sum of its proper divisors (1).

638607805879 is an equidigital number, since it uses as much as digits as its factorization.

638607805879 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 121927680, while the sum is 67.

The spelling of 638607805879 in words is "six hundred thirty-eight billion, six hundred seven million, eight hundred five thousand, eight hundred seventy-nine".