638684033887 has 2 divisors, whose sum is σ = 638684033888. Its totient is φ = 638684033886.

The previous prime is 638684033873. The next prime is 638684033921. The reversal of 638684033887 is 788330486836.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-638684033887 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638684033807) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319342016943 + 319342016944.

It is an arithmetic number, because the mean of its divisors is an integer number (319342016944).

Almost surely, 2^638684033887 is an apocalyptic number.

638684033887 is a deficient number, since it is larger than the sum of its proper divisors (1).

638684033887 is an equidigital number, since it uses as much as digits as its factorization.

638684033887 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 111476736, while the sum is 64.

The spelling of 638684033887 in words is "six hundred thirty-eight billion, six hundred eighty-four million, thirty-three thousand, eight hundred eighty-seven".